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#include <bits/stdc++.h>
using namespace std;
int main() {
int n, t, i, ctr;
cin >> t;
while (t--) {
cin >> n;
int a[i];
for (i = 0; i < n; i++) cin >> a[i];
ctr = 0;
for (i = 0; i < n; i++) {
if (a[i] >= i || a[i] >= (n - 1 - i)) ctr++;
}
if (n % 2 == 0 && a[n / 2] == a[n / 2 - 1] && a[n / 2] < n / 2) ctr--;
if (ctr != n)
cout << "No" << endl;
else
cout << "Yes" << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
for (int rewt = 0; rewt < t; rewt++) {
int n;
cin >> n;
vector<long long> v(n);
for (int i = 0; i < n; i++) cin >> v[i];
int left = 0;
int right = n - 1;
bool mozno = true;
while (right >= left) {
if (v[left] < left || v[right] < n - 1 - right) {
mozno = false;
break;
}
left++;
right--;
}
if (n % 2 == 1) {
if (mozno) {
cout << "Yes" << endl;
} else {
cout << "No" << endl;
}
} else {
if (!mozno) {
cout << "No" << endl;
} else {
int x = n / 2;
if (v[x - 1] >= x || v[x] >= x) {
cout << "Yes" << endl;
} else
cout << "No" << endl;
}
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
long long a[350000];
int main() {
int t;
cin >> t;
while (t--) {
int n, f = 0, t;
scanf("%d", &n);
for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
int mid = (n / 2) + (n % 2), k;
t = mid;
if (t + 1 <= n && a[t + 1] > a[t]) {
t++;
mid = t;
}
k = a[t];
mid--;
while (mid > 0) {
if (a[mid] < k)
k = a[mid];
else
k--;
if (k < 0 && mid > 0) f = 1;
mid--;
}
k = a[t];
mid = t + 1;
while (mid <= n) {
if (a[mid] < k)
k = a[mid];
else
k--;
if (k < 0 && mid <= n) f = 1;
mid++;
}
if (f == 1)
printf("No\n");
else
printf("Yes\n");
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
for (int i = 0; i < t; i++) {
int n, flag = 0, f = 0;
cin >> n;
vector<long long> v;
for (int j = 0; j < n; j++) {
long long a;
cin >> a;
v.push_back(a);
}
for (int j = 0; j <= n / 2; j++) {
if (v[j] < j) {
flag = 1;
}
}
int c = 0;
for (int j = v.size() - 1; j > n / 2; j--) {
if (v[j] < c) {
flag = 1;
}
c++;
}
for (int j = 0; j < n / 2 - 1; j++) {
if (v[j] < j) {
f = 1;
}
}
c = 0;
for (int j = v.size() - 1; j >= n / 2 - 1; j--) {
if (v[j] < c) {
f = 1;
}
c++;
}
if (flag == 1 && f == 1) {
cout << "No" << endl;
}
if (flag == 0 || f == 0) {
cout << "Yes" << endl;
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
void solve() {
int n;
cin >> n;
int mi = INT_MAX;
int ma = 0;
int a[n + 1];
for (int i = 1; i <= n; i++) {
cin >> a[i];
if (a[i] < i - 1) mi = min(i, mi);
if (a[i] < n - i) ma = max(i, ma);
}
if (ma + 1 <= mi - 1)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
int main() {
int t;
cin >> t;
while (t--) {
solve();
}
}
|
#include <bits/stdc++.h>
using namespace std;
int T, n;
int a[300004], v[300004];
int main() {
scanf("%d", &T);
while (T--) {
scanf("%d", &n);
bool flag = true;
for (int i = 1; i <= n; ++i) {
scanf("%d", &a[i]);
v[i] = min(i - 1, n - i);
}
if (n % 2 == 0) {
if (a[n / 2] > a[n / 2 + 1])
v[n / 2]++;
else
v[n / 2 + 1]++;
}
for (int i = 1; i <= n; ++i)
if (a[i] < v[i]) flag = false;
if (!flag)
printf("No\n");
else
printf("Yes\n");
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int middle(int a, int b, int c) {
if ((a <= b && b <= c) || (c <= b && b <= a))
return b;
else if ((b <= a && a <= c) || (c <= a && a <= b))
return a;
else
return c;
}
template <typename KeyType, typename ValueType>
std::pair<KeyType, ValueType> get_max(const std::map<KeyType, ValueType> &x) {
using pairtype = std::pair<KeyType, ValueType>;
return *std::max_element(x.begin(), x.end(),
[](const pairtype &p1, const pairtype &p2) {
return p1.second < p2.second;
});
}
static inline bool isvowel(char ch) {
static const std::string vowels("aeiouEAIOU");
return vowels.end() != std::find(vowels.begin(), vowels.end(), ch);
}
template <typename Map>
bool map_compare(Map const &lhs, Map const &rhs) {
return lhs.size() == rhs.size() &&
std::equal(lhs.begin(), lhs.end(), rhs.begin());
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
long long t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> v(n), c(n);
for (int i = 0; i < n; ++i) {
cin >> v[i];
c[i] = min(i, n - 1 - i);
}
if (n % 2 == 0) {
if (v[n / 2] > v[n / 2 - 1])
c[n / 2]++;
else
c[n / 2 - 1]++;
}
bool flag = true;
for (int i = 0; i < n; ++i) {
if (c[i] > v[i]) flag = false;
}
cout << (flag ? "YES" : "NO") << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
#pragma GCC optimize(2)
using namespace std;
const int N = 3e5 + 5, inf = 1e9 + 5;
int n, m;
int a[N];
int main() {
int t;
scanf("%d", &t);
while (t--) {
scanf("%d", &n);
for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
int ok = 1, p = -1;
for (int i = 0; i < n; ++i) {
if (a[i] < i) {
if (a[i] >= a[i - 1]) --a[i];
if (n - 1 - i > a[i]) ok = 0;
}
}
puts(ok ? "Yes" : "No");
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int T;
cin >> T;
while (T--) {
int n;
cin >> n;
int a[n];
bool ok = true;
bool f = true;
for (int i = 0; i < n; i++) {
cin >> a[i];
if (!ok) continue;
if (f && a[i] < i) {
f = false;
}
if (!f && a[i] < n - i - 1) ok = false;
}
if (n % 2 == 0 && a[n / 2] == (n / 2 - 1) && a[n / 2 - 1] == (n / 2 - 1))
ok = false;
if (ok)
cout << "Yes\n";
else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
long long int p1, p2;
long long int n;
cin >> n;
long long int a[n];
for (int i = 0; i < n; i++) {
cin >> a[i];
}
if (n == 1) {
cout << "Yes" << endl;
} else {
int count = 0, dount = 0;
for (int i = 0; i < n; i++) {
if (a[i] >= i) {
} else {
p1 = i;
count = 1;
break;
}
}
long long int m = 0;
for (int i = n - 1; i >= 0; i--) {
if (a[i] >= m) {
} else {
p2 = i;
dount = 1;
break;
}
m++;
;
}
if (count == 0 || dount == 0)
cout << "Yes" << endl;
else {
int count = 0, dount = 0;
if (p1 >= 1) p1--;
long long int m = 0;
for (int i = n - 1; i >= p1; i--) {
if (a[i] >= m) {
} else {
dount = 1;
break;
}
m++;
;
}
if (p2 >= 1) p2--;
for (int i = p2; i < n; i++) {
if (a[i] >= i) {
} else {
count = 1;
break;
}
}
if (count == 0 || dount == 0)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
long long int a[300005];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
long long int t, n, m, i, j, k, l;
cin >> t;
while (t--) {
cin >> n;
long long int max = -1;
long long int maxpos;
int flag = 0;
for (i = 1; i <= n; i++) {
cin >> a[i];
}
for (i = 1; i <= n; i++) {
if (a[i] < i - 1) break;
}
if (i <= n) {
long long int mini = a[i];
if (a[i] == a[i - 1]) mini--;
if (mini < 0) flag = 1;
for (j = i + 1; j <= n; j++) {
mini = min(mini - 1, a[j]);
if (mini < 0) {
flag = 1;
break;
}
}
}
if (flag == 0)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
while (a > 0 && b > 0) {
if (a > b)
a %= b;
else
b %= a;
}
return a + b;
}
long long a[1000000 + 5];
int32_t main() {
ios_base::sync_with_stdio(false);
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
for (long long i = 0; i < n; i++) {
cin >> a[i];
}
if (n == 1) {
cout << "Yes" << '\n';
continue;
}
if (n == 2) {
if (a[0] == 0 && a[1] == 0)
cout << "No" << '\n';
else
cout << "Yes" << '\n';
continue;
}
if (n % 2 == 1) {
long long k = 0;
bool can = true;
for (long long i = 0; i <= n / 2; i++) {
if (a[i] < k) can = false;
if (i != n / 2) k++;
}
for (long long i = n / 2 + 1; i < n; i++) {
k--;
if (a[i] < k) can = false;
}
if (can) {
cout << "Yes" << '\n';
} else {
cout << "No" << '\n';
}
} else {
long long k = 0;
bool can = true;
for (long long i = 0; i < n / 2 - 1; i++) {
if (a[i] < k) can = false;
if (i != n / 2 - 2) k++;
}
long long k0 = k;
for (long long i = n / 2 + 1; i < n; i++) {
if (a[i] < k) can = false;
k--;
}
if (can == true && ((a[n / 2 - 1] >= k0 + 2 && a[n / 2] >= k0 + 1) ||
(a[n / 2 - 1] >= k0 + 1 && a[n / 2] >= k0 + 2))) {
can = true;
} else {
can = false;
}
if (can) {
cout << "Yes" << '\n';
} else {
cout << "No" << '\n';
}
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
cin.tie(0), ios_base ::sync_with_stdio(0);
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long a[n];
for (int i = 0; i < n; ++i) cin >> a[i];
bool pos1 = 1;
bool sharp = 0;
int i = 0;
while (i < n && i < n - 1 && a[i] < a[i + 1]) {
i++;
}
long long pos = -1;
long long mx = 0;
for (int i = 0; i < n; ++i) {
if (a[i] >= i) {
mx = a[i];
pos = i;
} else
break;
}
while (pos < n - 1) {
if (a[pos] > a[pos + 1])
pos++;
else {
a[pos + 1] = a[pos] - 1;
pos++;
}
}
for (int i = 0; i < n; ++i)
if (a[i] < 0) pos1 = 0;
if (pos1)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int cases;
cin >> cases;
for (int tt = 0; tt < cases; tt++) {
int n;
cin >> n;
vector<int> v(n);
for (int i = 0; i < n; i++) {
cin >> v[i];
}
int ind1 = 0, ind2 = n - 1;
for (int i = 0; i < n; i++) {
if (i <= v[i]) {
ind1 = i;
} else {
break;
}
}
for (int i = n - 1; i >= 0; i--) {
int val = n - 1 - i;
if (v[i] >= val) {
ind2 = i;
} else {
break;
}
}
if (ind1 >= ind2) {
cout << "Yes" << endl;
} else
cout << "No" << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1000000000 + 7;
const long long int N = 1000000 + 6;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
long long int t;
cin >> t;
while (t--) {
long long int n;
cin >> n;
long long int a[n];
for (long long int i = 0; i < n; i++) {
cin >> a[i];
}
long long int cnt = 0, i = 0;
for (; i < n; i++) {
if (a[i] < i) {
cnt++;
break;
}
}
if (cnt == 0) {
cout << "Yes\n";
continue;
}
long long int j = n - 1;
for (; j >= i; j--) {
if (a[j] < n - j - 1) {
cnt++;
break;
}
}
if (cnt == 1 && (a[i - 1] == n - i - 1)) {
cout << "No\n";
continue;
};
if (cnt == 1) {
cout << "Yes\n";
continue;
}
cout << "No\n";
}
}
|
#include <bits/stdc++.h>
using namespace std;
long long arr[1000000];
int main() {
long long t, i, j, k, n, p1, p2;
cin >> t;
for (i = 0; i < t; i++) {
cin >> n;
for (j = 0; j < n; j++) {
cin >> arr[j];
}
p1 = -1;
p2 = -1;
for (j = 0; j < n; j++) {
if (arr[j] < j) {
p1 = j - 1;
break;
}
}
for (j = n - 1; j >= 0; j--) {
if (arr[j] < n - 1 - j) {
p2 = j + 1;
break;
}
}
if (p1 == -1 || p2 == -1) {
cout << "Yes" << endl;
} else {
if (p1 < p2) {
cout << "No" << endl;
} else {
cout << "Yes" << endl;
}
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
signed main() {
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long a[n], b[n];
for (int i = 0; i < n; i++) cin >> a[i];
int i = 0;
for (; i < n; i++) {
if (a[i] < i) break;
b[i] = i;
}
if (i == n) {
cout << "Yes\n";
continue;
} else {
long long push = 0, flag = 0;
for (int j = n - 1; j >= i; j--) {
if (a[j] < push) {
cout << "No\n";
flag = 1;
break;
}
push++;
}
push--;
if (flag == 0) {
if (push == b[i - 1]) {
if (a[i] > push || a[i - 1] > push) {
cout << "Yes\n";
} else {
cout << "No\n";
}
} else {
cout << "Yes\n";
}
} else {
continue;
}
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n, i, prefix, suffix;
cin >> n;
int a[n];
for (i = 0; i < n; i++) cin >> a[i];
for (i = 0; i < n; i++) {
if (i > a[i]) break;
prefix = i;
}
for (i = n - 1; i >= 0; i--) {
if ((n - i - 1) > a[i]) break;
suffix = i;
}
if (suffix <= prefix)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
long long int t;
cin >> t;
while (t--) {
long long int n;
cin >> n;
vector<long long int> vec(n + 2, 0);
for (long long int i = 1; i <= n; i++) cin >> vec[i];
vector<long long int> inc(n + 2, 0), dec(n + 2, 0);
for (long long int i = 1; i <= n; i++) {
if (vec[i] >= i - 1) {
inc[i] = 1;
}
inc[i] += inc[i - 1];
}
long long int c = 0;
for (long long int i = n; i >= 1; i--) {
if (vec[i] >= c) {
dec[i] = 1;
}
c++;
dec[i] += dec[i + 1];
}
bool bb = 0;
for (long long int i = 1; i <= n; i++) {
if (inc[i] == i && dec[i] == (n - i + 1)) {
bb = 1;
break;
}
}
if (bb == 1) {
cout << "Yes" << endl;
} else {
cout << "No" << endl;
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int middle(int a, int b, int c) {
if ((a <= b && b <= c) || (c <= b && b <= a))
return b;
else if ((b <= a && a <= c) || (c <= a && a <= b))
return a;
else
return c;
}
template <typename KeyType, typename ValueType>
std::pair<KeyType, ValueType> get_max(const std::map<KeyType, ValueType> &x) {
using pairtype = std::pair<KeyType, ValueType>;
return *std::max_element(x.begin(), x.end(),
[](const pairtype &p1, const pairtype &p2) {
return p1.second < p2.second;
});
}
static inline bool isvowel(char ch) {
static const std::string vowels("aeiouEAIOU");
return vowels.end() != std::find(vowels.begin(), vowels.end(), ch);
}
template <typename Map>
bool map_compare(Map const &lhs, Map const &rhs) {
return lhs.size() == rhs.size() &&
std::equal(lhs.begin(), lhs.end(), rhs.begin());
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> v(n);
for (int i = 0; i < n; ++i) {
cin >> v[i];
}
int inc = 0, dec = 0;
for (inc = 0; inc <= v[inc] and inc < n; ++inc)
;
for (dec = n - 1; n - 1 - dec <= v[dec] and dec >= 0; --dec)
;
cout << (inc + n - 1 - dec > n ? "YES" : "NO") << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int maxn = 500500;
const int inf = 0x3f3f3f3f;
int n, m;
int a[maxn];
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tn;
cin >> tn;
while (tn--) {
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i];
int i;
int p1 = 0, p2 = 0;
for (i = 1; i <= n; i++) {
if (a[i] + 1 >= i) {
p1 = i;
continue;
} else {
break;
}
}
for (i = n; i >= 0; i--) {
if (a[i] >= n - i) {
p2 = i;
continue;
} else
break;
}
if (p1 < p2)
cout << "No"
<< "\n";
else
cout << "Yes"
<< "\n";
}
}
|
#include <bits/stdc++.h>
using namespace std;
const long long inf = (long long)2e9;
const long long mod = 1000000007;
long long dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1};
long long powmod(long long a, long long p) {
long long ans = 1;
while (p) {
if (p & 1) ans *= a;
p /= 2;
a *= a;
ans %= mod;
a %= mod;
}
return ans;
}
long long mdinv(long long a) { return powmod(a, mod - 2); }
const long long N = 3e5 + 10;
long long v[N];
bool a[N], b[N];
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
long long tt;
cin >> tt;
while (tt--) {
long long n;
cin >> n;
for (long long i = 0; i < (long long)n; i++) cin >> v[i];
for (long long i = 0; i < (long long)n; i++) a[i] = b[i] = 0;
for (long long i = 0; i < (long long)n; i++) {
a[i] = (v[i] >= i);
b[i] = (v[i] >= (n - 1 - i));
}
for (long long i = 1; i < n; i++) a[i] &= a[i - 1];
for (long long i = n - 2; i >= 0; i--) b[i] &= b[i + 1];
bool ans = 0;
for (long long i = 0; i < (long long)n; i++)
if (a[i] && b[i]) ans = 1;
cout << (ans ? "Yes" : "No") << "\n";
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
int query;
cin >> query;
while (query--) {
int n;
cin >> n;
vector<int> v(n);
for (int i = 0; i < n; i++) cin >> v[i];
int l = n, r = n;
for (int i = 0; i < n; i++) {
if (v[i] < i) {
l = i;
break;
}
}
reverse(v.begin(), v.end());
for (int i = 0; i < n; i++) {
if (v[i] < i) {
r = i;
break;
}
}
reverse(v.begin(), v.end());
if (l + r >= n + 1)
cout << "Yes\n";
else
cout << "No\n";
}
}
|
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1001010;
int a[maxn];
void solve() {
int n;
cin >> n;
for (int i = 0; i < n; ++i) {
cin >> a[i];
}
int cnt = 0;
for (int i = 0; i < n and a[i] >= i; ++i, ++cnt) {
}
for (int i = n - 1; i >= 0 and a[i] >= n - 1 - i; --i, ++cnt) {
}
cout << (cnt > n ? "Yes" : "No") << endl;
}
int main() {
int t;
cin >> t;
while (t--) {
solve();
}
}
|
#include <bits/stdc++.h>
using namespace std;
void c_p_c() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
void ans() {
long long num;
cin >> num;
long long A[num];
for (long long i = 0; i < num; i++) cin >> A[i];
long long i, j;
for (i = 0; i < num; i++) {
if (A[i] < i) break;
}
for (j = num - 1; j >= 0; j--) {
if (A[j] < num - j - 1) break;
}
if (i >= j + 2)
cout << "YES"
<< "\n";
else
cout << "NO"
<< "\n";
}
int32_t main() {
c_p_c();
long long x;
cin >> x;
while (x--) ans();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t, n;
cin >> t;
while (t--) {
cin >> n;
long long int a[n];
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int p = -1, s = n;
for (int i = 0; i < n; i++) {
if (a[i] < i) break;
p = i;
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] < n - 1 - i) break;
s = i;
}
if (s <= p)
cout << "Yes\n";
else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 314;
const int INF = 1e9;
const double PI = acos(-1);
const int MOD = 1e9 + 7;
const double eps = 1e-9;
long long a[N];
int dpl[N], dpr[N];
void solve() {
int n;
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
}
if (n == 1) {
cout << "Yes\n";
return;
}
int up = 1;
int idx = 0;
int ds = n + 1;
for (int i = 2; i <= n; ++i) {
if (a[i] < i - 1) {
ds = i;
break;
}
}
for (int i = ds; i <= n; ++i) {
a[i] = min(a[i], a[i - 1] - 1);
if (a[i] < 0) {
cout << "No\n";
return;
}
if (a[i] == 0 && i != n) {
cout << "No\n";
return;
}
}
cout << "Yes\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
cin >> t;
while (t--) solve();
}
|
#include <bits/stdc++.h>
using namespace std;
const int maxn = 3e5 + 7;
int arr[maxn], L[maxn], R[maxn], n;
void solve() {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> arr[i];
}
L[0] = 1, R[n + 1] = 1;
for (int i = 1; i <= n; i++) {
if (arr[i] >= i - 1) {
L[i] = L[i - 1];
} else {
L[i] = 0;
}
}
for (int i = n; i >= 1; i--) {
if (arr[i] >= n - i) {
R[i] = R[i + 1];
} else {
R[i] = 0;
}
}
for (int i = 1; i <= n; i++) {
if (L[i] && R[i]) {
cout << "Yes" << endl;
return;
}
}
cout << "No" << endl;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int test = 1;
cin >> test;
while (test--) {
solve();
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const long long N = 3e5 + 5;
long long t, n, a[N];
bool possible() {
for (long long i = 0, j = n - 1; i <= j; i++, j--)
if (a[i] < i || a[j] < i) return 0;
return n % 2 || a[n / 2 - 1] > n / 2 - 1 || a[n / 2] > n / 2 - 1;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> t;
while (t--) {
cin >> n;
for (long long i = 0; i < n; i++) cin >> a[i];
cout << (possible() ? "Yes\n" : "No\n");
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
long long int t, i, j, k;
cin >> t;
while (t--) {
long long int n, n1, n2;
cin >> n;
long long int a[n], b[n], c[n];
for (i = 0; i < n; i++) {
cin >> a[i];
c[i] = a[i];
b[i] = a[i];
}
long long int pre = 0, post = 0, i1 = 0, j1 = (n - 1), i2, j2, count1 = 0,
count2 = 0;
while (i1 < n && j1 >= 0) {
count1 = 0;
count2 = 0;
if (a[i1] >= pre && i1 <= (n - 1) && (i1 == 0 || (i1 - i2) == 1)) {
c[i1] = pre;
i2 = i1;
count1++;
}
if (a[j1] >= post && j1 >= 0 && (j1 == (n - 1) || (j2 - j1) == 1)) {
b[j1] = post;
j2 = j1;
count2++;
}
pre++;
post++;
if (i1 < (n - 2)) i1++;
if (j1 > 0) j1--;
if (count1 == 0 && count2 == 0) break;
}
if ((j2 - i2) <= 0)
cout << "Yes"
<< "\n";
else if ((j2 - i2) == 1) {
if ((a[j2] == a[i2]) && (b[j2] == c[i2]))
cout << "No"
<< "\n";
else
cout << "Yes"
<< "\n";
} else
cout << "No"
<< "\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> v;
bool solve() {
int i, j;
for (i = 1; i < n; i++) {
if (v[i] < i) {
i--;
break;
}
}
if (i == n) return true;
for (j = n - 2; j >= 0; j--) {
if (v[j] < n - 1 - j) {
j++;
break;
}
}
return (i >= j);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
;
while (t--) {
cin >> n;
v.resize(n);
for (int i = 0; i < n; i++) cin >> v[i];
(solve()) ? cout << "YES" : cout << "NO";
cout << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long a[n];
for (long long i = 0; i < n; i++) cin >> a[i];
int pref = -1, suff = n;
for (int i = 0; i < n; i++) {
if (a[i] < i) break;
pref = i;
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] < (n - 1 - i)) break;
suff = i;
}
if (suff <= pref)
cout << "Yes\n";
else
cout << "No\n";
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n, num[350004], count = 0;
cin >> n;
for (int i = 0; i < n; i++) cin >> num[i];
if (n == 1)
cout << "YES\n";
else {
for (int i = 0; i < n; i++) {
if (i < n / 2) {
if (num[i] < i) count = 1;
} else {
if ((num[i] < n - i - 1) ||
((num[n / 2 - 1] == num[n / 2]) && (num[n / 2] == n / 2 - 1)))
count = 1;
}
}
if (count == 0)
cout << "YES\n";
else
cout << "NO\n";
}
count = 0;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
void solve() {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int start = 0;
for (int i = 0; i < n; i++) {
if (a[i] < i) break;
start = i;
}
int end = n - 1;
for (int i = 0; i < n; i++) {
if (a[n - i - 1] < i) break;
end = n - i - 1;
}
if (end <= start)
cout << "Yes"
<< "\n";
else
cout << "No"
<< "\n";
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int t = 1;
cin >> t;
while (t--) {
solve();
}
return 0;
}
|
#include <bits/stdc++.h>
long long a[300005];
int main() {
int t;
scanf("%d", &t);
while (t--) {
int n, i, flag = 1;
scanf("%d", &n);
for (i = 0; i < n; i++) scanf("%lld", &a[i]);
if (n == 1) {
printf("YES\n");
continue;
}
if (n == 2 && a[0] == 0 && a[n - 1] == 0) {
printf("NO\n");
continue;
}
for (i = 1; i < n - 1; i++) {
if (a[i] < i && a[i] < (n - 1 - i)) {
flag = 0;
break;
}
if (a[i] == a[i + 1]) {
if (a[i] == i && a[i + 1] == (n - i - 2)) {
flag = 0;
break;
}
}
}
if (flag)
printf("YES\n");
else
printf("NO\n");
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
long long int a[1000000], flag = 0;
long long int n;
cin >> n;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int start, end;
for (start = 0; start < n; start++) {
if (a[start] < start) break;
}
start;
for (end = n - 1; end >= 0; end--) {
if (a[end] < n - end - 1) break;
}
if (start > end + 1) flag = 1;
if (flag == 1)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
}
|
#include <bits/stdc++.h>
using ll = long long;
using ull = unsigned long long;
using namespace std;
int del(int n, int a) {
for (int i = 2; i * i <= n; i++)
if (n % i == 0 && i != a) return i;
return -1;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) cin >> a[i];
int p = -1, s = n;
for (int i = 0; i < n; ++i) {
if (a[i] < i) break;
p = i;
}
for (int i = n - 1; i >= 0; --i) {
if (a[i] < (n - 1) - i) break;
s = i;
}
if (s <= p)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
void B() {
int t, n;
cin >> t;
while (t--) {
int l = INT_MAX, r = INT_MAX;
cin >> n;
int arr[n];
for (int i = 0; i < (n); i++) cin >> arr[i];
for (int i = 0; i < (n); i++) {
if (arr[i] < i) {
l = i - 1;
break;
}
}
if (l == INT_MAX)
cout << "Yes\n";
else {
for (int i = n - 1; i >= l; i--) {
if (arr[i] < (n - i - 1)) {
r = i;
break;
}
}
if (r == INT_MAX)
cout << "Yes\n";
else
cout << "No\n";
}
}
}
int main() {
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
};
B();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
bool check(vector<int> v, vector<int> v1) {
for (int i = 0; i < v.size(); i++) {
if (v[i] < v1[i]) return false;
}
return true;
}
int main() {
int t, n, x, mid;
vector<int> v, v1, v2;
cin >> t;
while (t--) {
cin >> n;
for (int i = 0; i < n; i++) {
cin >> x;
v.push_back(x);
}
if (n % 2 == 1) {
mid = n / 2;
for (int i = 0; i < n; i++) {
if (i <= mid)
v1.push_back(i);
else
v1.push_back(n - 1 - i);
}
if (check(v, v1))
cout << "YES" << endl;
else
cout << "NO" << endl;
} else {
mid = n / 2;
for (int i = 0; i < n; i++) {
if (i <= mid)
v1.push_back(i);
else
v1.push_back(n - 1 - i);
if (i <= mid - 2)
v2.push_back(i);
else
v2.push_back(n - 1 - i);
}
if (check(v, v1) || check(v, v2))
cout << "YES" << endl;
else
cout << "NO" << endl;
}
v.clear();
v1.clear();
v2.clear();
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
void solve() {
int n;
cin >> n;
int a[n];
for (int i = 0; i < n; i++) cin >> a[i];
int left = 0;
int right = n - 1;
for (int i = 0; i < n; i++) {
if (a[i] >= i)
left = i;
else
break;
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] >= n - i - 1)
right = i;
else
break;
}
if (left >= right)
cout << "YES" << endl;
else
cout << "NO" << endl;
}
int main() {
int t;
cin >> t;
while (t--) solve();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const long long N = 1e6 + 10;
const long long INF = 1e18;
const long long inf = -1e18;
const long long MOD = 1e9 + 7;
long long n, t, k, s, q, a[N];
int main() {
cin >> q;
for (int i = 1; i <= q; i++) {
cin >> n;
k = 0;
t = 0;
for (int j = 1; j <= n; j++) {
cin >> a[j];
}
for (int j = 1; j <= n; j++) {
if (a[j] >= j - 1) {
k++;
} else {
break;
}
}
for (int j = n; j >= 1; j--) {
if (a[j] >= n - j) {
t++;
} else {
break;
}
}
if (k > n - t) {
cout << "YES" << endl;
} else {
cout << "NO" << endl;
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
long long int dp[45];
long long int a[1000006];
int main() {
long long int mod, t, k = 0, n, i, m, x, j = 0, l, c = 0, r = 0, w, s = 0,
d = 0, f = 0, sum = 0, mul, mx1, mx, s1 = 10000000,
s2 = 0;
cin >> t;
while (t--) {
d = 0;
f = 0;
cin >> n;
for (i = 0; i < n; i++) {
cin >> m;
if (f == 0 && d <= m) {
d++;
} else if (f != 3) {
if (f == 0) {
d = min(k - 1, n - d - 1);
f = 2;
}
if (d >= 0 && d <= m) {
d--;
} else {
f = 3;
}
}
k = m;
}
if (f == 3) {
cout << "No" << endl;
} else {
cout << "Yes" << endl;
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int max_size = 3e5 + 100;
const int mod = 1e9 + 7;
const long long dis = 2e16;
long long a[max_size];
int main() {
ios_base::sync_with_stdio(false);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
for (int i = 0; i < n; i++) cin >> a[i];
if (n == 1) {
cout << "Yes" << endl;
continue;
}
bool vis[n + 5][2];
memset(vis, 0, sizeof(vis));
vis[0][0] = 1;
vis[n - 1][1] = 1;
for (int i = 1; i < n; i++) {
vis[i][0] = (a[i] >= i) & vis[i - 1][0];
vis[n - 1 - i][1] = (a[n - 1 - i] >= i) & vis[n - i][1];
}
bool check = 0;
check = (a[0] >= n - 1) && vis[1][1];
check |= (a[n - 1] >= n - 1) && vis[n - 2][0];
for (int i = 1; i < n - 1; i++) {
check |= (a[i] >= max(i, n - i - 1)) & vis[i - 1][0] & vis[i + 1][1];
}
if (check)
cout << "Yes";
else
cout << "No";
cout << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using pii = pair<int, int>;
using graph = vector<vi>;
void go() {
int n;
cin >> n;
vi A(n);
for (int& i : A) cin >> i;
vi left(n, 0), right(n, 0);
for (int i = 0; i < n && A[i] >= i; i++) left[i] = i;
for (int i = n - 1; i >= 0 && A[i] >= (n - 1 - i); i--) right[i] = n - 1 - i;
bool poss = false;
for (int i = 0; i < n - 1; i++) {
if ((left[i] == i && right[i + 1] == n - 1 - (i + 1))) {
if (left[i] == right[i + 1]) {
if (A[i] > left[i] || A[i + 1] > right[i + 1]) poss = true;
} else {
poss = true;
}
}
}
if (poss || n == 1)
cout << "Yes\n";
else
cout << "No\n";
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int t;
cin >> t;
while (t--) go();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int mang[4000009];
int main() {
int t;
cin >> t;
while (t > 0) {
int n;
cin >> n;
int tang = 0, giam = 0;
int ii = 0;
for (int i = 0; i < n; i++) {
cin >> mang[i];
if (mang[i] >= i && ii == i) {
ii++;
tang = i;
}
}
int k = 0;
for (int j = n - 1; j >= tang; j--) {
if (mang[j] >= k) {
k++;
giam = j;
} else {
break;
}
}
if (tang >= giam) {
cout << "YES" << endl;
} else {
cout << "NO" << endl;
}
t--;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
long long int power(long long int a, long long int b, long long int m) {
if (b == 0) return 1;
if (b == 1) return a % m;
long long int t = power(a, b / 2, m);
t = (t * t) % m;
if (b & 1) t = (t * a) % m;
return t;
}
long long int gcd(long long int a, long long int b) {
if (b == 0) {
return a;
} else {
return gcd(b, a % b);
}
}
int main() {
long long int t;
cin >> t;
while (t--) {
long long int n;
cin >> n;
long long int a[n];
long long int flag = 0;
for (long long int i = 0; i < n; i++) {
cin >> a[i];
}
long long int k = -1;
for (long long int i = 0; i < n; i++) {
if (a[i] < i) {
k = i - 1;
break;
}
}
if (k != -1) {
for (long long int i = k; i < n; i++) {
if (a[i] < n - 1 - i) {
flag = 1;
break;
}
}
if (flag) {
cout << "No" << endl;
} else {
cout << "Yes" << endl;
}
} else {
if (flag) {
cout << "No" << endl;
} else {
cout << "Yes" << endl;
}
}
}
}
|
#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:2000000000")
using namespace std;
vector<long long> used, parent, a, cnt_child;
struct edge {
long long idx, st;
};
bool cmp(long long x, long long y) { return a[x] > a[y]; }
bool fl = true;
void dfs(long long start, long long p, vector<vector<long long> >& g,
long long h) {
used[start] = 1;
parent[start] = p;
for (auto i : g[start]) {
if (!used[i]) {
dfs(i, start, g, h + 1);
cnt_child[start] += cnt_child[i] + 1;
}
}
if (cnt_child[start] + h > g[start].size()) {
fl = false;
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
vector<long long> a(n);
for (long long i = 0; i < n; ++i) {
cin >> a[i];
}
long long l = n + 1, r = -1;
for (long long i = 0; i < n; ++i) {
if (a[i] < i) {
l = i - 1;
break;
}
}
for (long long i = n - 1; i >= 0; --i) {
if (a[i] < (n - i - 1)) {
r = i + 1;
break;
}
}
if (l >= r) {
cout << "Yes\n";
} else {
cout << "No\n";
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int tc;
cin >> tc;
while (tc--) {
int n;
cin >> n;
vector<int> a(n);
for (int& i : a) cin >> i;
int p, q;
for (p = 0; p < n; p++) {
if (a[p] < p) {
p--;
break;
}
}
for (q = n - 1; q >= 0; q--)
if (a[q] < n - q - 1) {
q++;
break;
}
cout << (p >= q ? "YES\n" : "NO\n");
}
}
|
#include <bits/stdc++.h>
const int maxx = 3e5 + 7;
const int maxn = 1e9 + 1;
using namespace std;
int t, n;
int a[maxx];
int main() {
scanf("%d", &t);
while (t--) {
scanf("%d", &n);
for (int i = 0; i < n; i++) {
scanf("%d", &a[i]);
}
if (n == 1)
cout << "Yes" << endl;
else if (n == 2) {
if (a[0] == 0 && a[1] == 0)
cout << "No" << endl;
else
cout << "Yes" << endl;
} else {
int flag = 0;
if (n % 2 == 0) {
for (int i = 0; i < n / 2; i++) {
if (a[i] < i) {
flag = 1;
break;
}
}
for (int i = n / 2; i < n; i++) {
if (a[i] < n - i - 1) {
flag = 1;
break;
}
}
if (a[n / 2 - 1] == a[n / 2] && a[n / 2 - 1] == n / 2 - 1) {
flag = 1;
}
if (flag)
cout << "No" << endl;
else
cout << "Yes" << endl;
} else {
for (int i = 0; i < n / 2; i++) {
if (a[i] < i) {
flag = 1;
break;
}
}
for (int i = n / 2; i < n; i++) {
if (a[i] < n - i - 1) {
flag = 1;
break;
}
}
if (flag)
cout << "No" << endl;
else
cout << "Yes" << endl;
}
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int MAX = 3 * 1e5 + 10;
int n, a[MAX];
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
bool ans, asc, des;
int t;
cin >> t;
while (t--) {
cin >> n;
for (int i = 0; i < n; i++) cin >> a[i];
ans = asc = true;
for (int i = 0, j = 0; i < n && ans; i++) {
if (asc)
if (a[i] < i) {
asc = false;
if (i)
if (a[i] == n - i - 1 && a[i] == a[i - 1]) ans = false;
}
if (!asc)
if (a[i] < n - i - 1) ans = false;
}
des = true;
for (int i = 1; i < n; i++) {
des = des && (a[i] < a[i - 1]);
}
if (ans || des)
cout << "Yes" << '\n';
else
cout << "No" << '\n';
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e6 + 10;
const int mod = 1e9 + 7;
int a[maxn];
int main() {
int n;
cin >> n;
while (n--) {
int len;
cin >> len;
for (int i = 1; i <= len; i++) scanf("%d", &a[i]);
bool ok = 1;
bool yes = 0;
int cnt = 0;
int aa = -1, b = -1;
for (int i = 1; i <= len; i++) {
if (a[i] >= cnt)
++cnt;
else {
aa = i - 1;
ok = 0;
break;
}
}
yes |= ok;
ok = 1;
cnt = 0;
for (int i = len; i >= 1; i--) {
if (a[i] >= cnt)
++cnt;
else {
b = i + 1;
ok = 0;
break;
}
}
yes |= ok;
ok = 1;
cnt = 0;
yes |= (aa >= b);
if (yes)
cout << "Yes" << endl;
else
cout << "no" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
long long Min(long long a, long long b) { return (a < b) ? a : b; }
long long Max(long long a, long long b) { return (a < b) ? b : a; }
long long gcd(long long m, long long n) {
if (n == 0) return m;
return gcd(n, m % n);
}
long long lcm(long long m, long long n) { return m * n / gcd(m, n); }
long long a[500005];
long long pos_l[500005], pos_r[500005];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
long long tc;
cin >> tc;
while (tc--) {
long long n;
cin >> n;
for (int i = 0; i < n; i++) {
cin >> a[i];
pos_l[i] = pos_r[i] = 0;
}
for (int i = 0; i < n; i++) {
if (a[i] >= i)
pos_l[i] = 1;
else
break;
}
for (int i = 0; i < n; i++) {
if (a[n - i - 1] >= i)
pos_r[n - i - 1] = 1;
else
break;
}
long long suc = 0;
for (int i = 0; i < n; i++) {
if (pos_l[i] && pos_r[i]) {
cout << "Yes\n";
suc = 1;
break;
}
}
if (suc == 0) {
cout << "No\n";
}
}
exit(0);
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
cin.tie(nullptr);
ios::sync_with_stdio(false);
int q;
cin >> q;
while (q--) {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
bool ok = 1;
vector<int> b = a;
int i = 0;
for (; i < n - 1; i++) {
if (a[i] >= i) {
a[i] = i;
} else
break;
}
if (i > 0 && a[i] == a[i - 1]) {
i--;
}
a[i] = b[i];
for (; i < n - 1; i++) {
if (a[i + 1] >= a[i]) {
a[i + 1] = a[i] - 1;
}
}
for (int i = 0; i < n; i++) {
if (a[i] < 0) ok = 0;
}
if (ok) {
cout << "Yes" << endl;
} else {
cout << "No" << endl;
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> a(n);
for (auto &i : a) {
cin >> i;
}
vector<bool> pref(n);
vector<bool> suf(n);
pref[0] = true;
for (int i = 1; i < n; ++i) {
if (a[i] >= i && pref[i - 1]) {
pref[i] = true;
}
}
suf[n - 1] = true;
for (int i = n - 2; i >= 0; --i) {
if (a[i] >= (n - i - 1) && suf[i + 1]) {
suf[i] = true;
}
}
bool flag = true;
for (int i = 0; i < n; ++i) {
if (pref[i] && suf[i]) {
cout << "Yes" << '\n';
flag = false;
break;
}
}
if (flag) {
cout << "No\n";
}
}
return 0;
}
|
#include <bits/stdc++.h>
using ll = long long;
using namespace std;
const int N = 1e6 + 6, mod = 1e9 + 7;
int t, a[N], l[N], r[N];
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> t;
while (t--) {
int n;
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i];
}
bool yes = 1;
for (int i = 1; i <= n; i++) {
if (a[i] < i - 1) {
yes = 0;
}
l[i] = yes;
}
yes = 1;
for (int i = n; i >= 1; i--) {
if (a[i] < n - i) {
yes = 0;
}
r[i] = yes;
}
l[0] = 1;
r[n + 1] = 1;
a[0] = -INT_MAX;
a[n + 1] = INT_MAX;
yes = 0;
for (int k = 0; k <= n; k++) {
if (l[k] && r[k + 1] && (k - 1 < a[k + 1] || k - 1 > a[k + 1])) {
yes = 1;
}
}
if (yes) {
cout << "Yes\n";
} else {
cout << "No\n";
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
template <class t>
inline t read(t &x) {
x = 0;
char c = getchar();
bool f = 0;
while (!isdigit(c)) f |= c == '-', c = getchar();
while (isdigit(c)) x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
if (f) x = -x;
return x;
}
template <class t>
inline void write(t x) {
if (x < 0) {
putchar('-'), write(-x);
} else {
if (x > 9) write(x / 10);
putchar('0' + x % 10);
}
}
const int N = 3e5 + 5;
int a[N];
void doit() {
int n, l = 0, r;
r = read(n) + 1;
for (int i = 1; i <= n; i++) read(a[i]);
while (a[l + 1] >= l && l + 1 <= n) l++;
while (a[r - 1] >= n - r + 1 && r - 1 >= 1) r--;
if (l >= r)
puts("Yes");
else
puts("No");
}
signed main() {
int t;
read(t);
while (t--) doit();
}
|
#include <bits/stdc++.h>
using namespace std;
const int maxn = 3e5 + 5;
const int mod = 998244353;
const long long INF = 0x3f3f3f3f3f3f3f3f;
int n, a[maxn], b[maxn];
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
while (t--) {
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i];
for (int i = 1; i <= n; i++) b[i] = a[i];
int ff = 0;
for (int i = 1; i < n; i++) {
b[i + 1] = min(b[i + 1], b[i] - 1);
if (b[i + 1] < 0) {
ff = 1;
break;
}
}
if (!ff) {
cout << "Yes" << '\n';
continue;
}
a[0] = -1;
int pos = -1;
for (int i = 1; i < n; i++) {
int temp = a[i];
a[i] = min(a[i], a[i - 1] + 1);
if (a[i] >= a[i + 1]) {
a[i] = temp;
pos = i;
break;
}
}
if (pos == -1) {
cout << "Yes" << '\n';
continue;
}
int flag = 0;
for (int i = pos; i < n; i++) {
a[i + 1] = min(a[i + 1], a[i] - 1);
if (a[i + 1] < 0) {
flag = 1;
break;
}
}
if (flag)
cout << "No" << '\n';
else
cout << "Yes" << '\n';
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int t = 1;
cin >> t;
while (t--) {
long long int i, n;
cin >> n;
long long int a[n];
for (i = 0; i < n; i++) cin >> a[i];
int prefix = -1, suffix = n;
for (i = 0; i < n; i++) {
if (a[i] < i) break;
prefix = i;
}
for (i = n - 1; i >= 0; i--) {
if (a[i] < n - 1 - i) break;
suffix = i;
}
if (suffix <= prefix)
cout << "YES" << endl;
else
cout << "NO" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
long long a[n];
bool flag = true;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int l = 0, r = (n - 1), num = 0;
while (l <= r) {
if ((l + 1) == r) {
if ((a[l] >= num && a[r] >= (num + 1)) ||
(a[l] >= (num + 1) && a[r] >= num)) {
break;
} else {
flag = false;
}
}
if (a[l] >= num) {
a[l] = num;
} else {
flag = false;
}
if (a[r] >= num) {
a[r] = num;
} else {
flag = false;
}
l++;
r--;
num++;
}
cout << (flag ? "YES" : "NO") << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long arr[n];
for (long long i = 0; i < n; i++) cin >> arr[i];
long long p = 0;
while (p < n) {
if (arr[p] < p) break;
p++;
}
--p;
long long s = n - 1;
while (s >= 0) {
if (arr[s] < n - s - 1) break;
s--;
}
++s;
if (s <= p || (s == p + 1 && arr[s] != arr[p]))
cout << "Yes";
else
cout << "No";
cout << "\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007, N = 3e5 + 5, M = 1e5 + 5, INF = 0x3f3f3f3f;
long long powmod(long long a, long long b) {
long long res = 1;
a %= mod;
assert(b >= 0);
for (; b; b >>= 1) {
if (b & 1) res = res * a % mod;
a = a * a % mod;
}
return res;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
int a[N];
int main(void) {
ios::sync_with_stdio(false);
int T;
cin >> T;
while (T--) {
int n;
cin >> n;
bool flag = 1;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int l = 0, r = n - 1;
while (a[l] >= l) ++l;
while (a[r] >= n - 1 - r) --r;
if (l > r + 1)
puts("YES");
else
puts("NO");
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> v(n), temp1(n), temp2(n);
for (int i = 0; i < n; i++) cin >> v[i];
int indf = -1, indb = -1;
for (int i = 0; i < n; i++) {
if (v[i] < i) {
break;
}
indf = i;
}
for (int i = n - 1; i >= 0; i--) {
if (v[i] < (n - 1) - i) {
break;
}
indb = i;
}
if (indb <= indf) {
cout << "Yes\n";
} else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 100;
int a[N];
int main(void) {
int t;
scanf("%d", &t);
while (t--) {
int n;
cin >> n;
for (int i = 0; i < n; i++) scanf("%d", &a[i]);
int toR = 0;
int toL = n - 1;
for (int i = 0; i < n; i++) {
if (a[i] >= i)
toR = i;
else
break;
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] >= (n - 1 - i))
toL = i;
else
break;
}
if (toL - toR == 1 && a[toL] == a[toR])
puts("NO");
else if (toL - toR > 1)
puts("NO");
else
puts("YES");
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const long long oo = (long long)1e16;
const int A = 26;
long long n, m, ID, l, nb, a, b;
long long t[300005];
long long t1[300005];
long long t2[300005];
long long dp[300005];
vector<int> v;
string s;
int main() {
ios_base::sync_with_stdio(0);
cin >> nb;
while (nb--) {
cin >> n;
for (int i = 0; i < n; i++) cin >> t[i];
a = n;
for (int i = 0; i < n; i++) {
if (t[i] < i) {
a = i;
break;
}
}
bool test = true;
for (int i = a - 1; i < n; i++) {
if (t[i] < (n - 1 - i)) test = false;
}
if (test)
cout << "Yes\n";
else
cout << "No\n";
}
}
|
#include <bits/stdc++.h>
using namespace std;
int u[300005];
int main() {
int t;
scanf("%d", &t);
while (t--) {
int n;
scanf("%d", &n);
for (int i = 1; i <= n; i++) scanf("%d", &u[i]);
int i, j;
for (i = 1; i <= n; i++) {
if (u[i] < i - 1) break;
}
for (j = n; j >= 1; j--) {
if (u[j] < n - j) break;
}
if (n >= 3) {
if (i - 2 >= j)
printf("Yes\n");
else
printf("No\n");
} else {
if (n == 1)
printf("Yes\n");
else {
if (u[1] == 0 && u[2] == 0)
printf("No\n");
else
printf("Yes\n");
}
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
const int N = 3 * 1e5 + 100;
int t, n, a[N];
int main() {
scanf("%d", &t);
while (t--) {
scanf("%d", &n);
for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
bool bl = 1;
vector<int> p;
int l, r;
l = 0;
r = (int)1e9;
for (int i = 1; i <= n; i++) {
if (a[i] < i - 1 && a[i] >= n - i) r = min(r, i);
if (a[i] >= i - 1 && a[i] < n - i) l = max(l, i);
if (a[i] >= i - 1 && a[i] >= n - i) p.push_back(i);
if (a[i] < i - 1 && a[i] < n - i) {
bl = 0;
break;
}
}
if (!bl) {
printf("No\n");
continue;
}
for (int i = 0; i < (int)p.size(); i++) {
if (r > p[i] && l < p[i]) {
bl = 0;
break;
}
}
if (bl)
printf("No\n");
else
printf("Yes\n");
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
int a[n];
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int prefix_end = -1, suffix_end = n;
for (int i = 0; i < n; i++) {
if (a[i] < i) {
break;
}
prefix_end = i;
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] < (n - 1) - i) {
break;
}
suffix_end = i;
}
if (suffix_end <= prefix_end) {
cout << "Yes";
} else {
cout << "No";
}
cout << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
namespace IO {
static char buf[1 << 20], *fs, *ft;
inline char gc() {
if (fs == ft) {
ft = (fs = buf) + fread(buf, 1, 1 << 20, stdin);
if (fs == ft) return EOF;
}
return *fs++;
}
inline int read() {
int x = 0, f = 1;
char s = getchar();
while (s < '0' || s > '9') {
if (s == '-') f = -f;
s = getchar();
}
while (s >= '0' && s <= '9') {
x = x * 10 + s - '0';
s = getchar();
}
return x * f;
}
} // namespace IO
using IO::read;
const int N = 300100;
int T;
int n;
int a[N];
int sum[N], sum1[N];
int vis[N], vis1[N];
inline void solve() {
int opt = 0;
n = read();
memset(sum, 0, sizeof(sum));
memset(sum1, 0, sizeof(sum1));
for (register int i = 1; i <= n; ++i) {
vis[i] = 0;
a[i] = read();
if (a[i] >= i - 1) vis[i] = 1;
sum[i] = sum[i - 1] + vis[i];
}
for (int i = n; i >= 1; --i) {
vis1[i] = 0;
if (a[i] >= n - i) vis1[i] = 1;
sum1[i] = sum1[i + 1] + vis1[i];
}
if (sum[n] == n) {
puts("Yes");
return;
}
if (sum1[1] == n) {
puts("Yes");
return;
}
for (register int i = 1; i <= n; ++i)
if (sum[i] + sum1[i + 1] == n && !(a[i] == a[i + 1] && a[i] == i - 1)) {
puts("Yes");
opt = 1;
break;
}
if (opt == 0) puts("No");
}
int main() {
T = read();
while (T--) solve();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 3e5 + 10;
typedef int ar[MAXN];
namespace HABIT {
template <typename T>
inline T Max(T a) {
return a;
}
template <typename T, typename... Args>
inline T Max(T a, Args... args) {
T b = Max(args...);
return (a > b) ? a : b;
}
template <typename T>
inline T Min(T a) {
return a;
}
template <typename T, typename... Args>
inline T Min(T a, Args... args) {
T b = Min(args...);
return (a < b) ? a : b;
}
inline char gc() { return getchar(); }
inline int read() {
register int ans = 0;
register char c = gc();
register bool neg = 0;
while (c < 48 || c > 57) neg ^= !(c ^ '-'), c = gc();
while (c >= 48 && c <= 57) ans = (ans << 3) + (ans << 1) + (c ^ 48), c = gc();
return neg ? -ans : ans;
}
char Output_Ans[1 << 20 | 1], *Output_Cur = Output_Ans;
inline void output() {
Output_Cur -= fwrite(Output_Ans, 1, Output_Cur - Output_Ans, stdout);
}
inline void print(char c) {
if (Output_Cur - Output_Ans + 1 >> 20) output();
*(Output_Cur++) = c;
}
inline void print(char *s) {
while (*s) print(*(s++));
}
inline void print(unsigned long long int x) {
if (!x) {
print('0');
return;
}
char buf[30] = {0}, *p = buf + 28;
while (x) *(p--) = x % 10 + 48, x /= 10;
print(p + 1);
}
inline void print(unsigned int x) { print((unsigned long long int)x); }
inline void print(long long int x) {
if (x < 0) print('-'), x = -x;
print((unsigned long long int)x);
}
inline void print(int x) {
if (x < 0) print('-'), x = -x;
print((unsigned long long int)x);
}
} // namespace HABIT
using namespace HABIT;
ar ar_d_Num1, ar_d_Num2;
inline bool alw() {
int d_N = read();
for (register int i = 1, I = d_N; i <= I; i++) {
int d_Tmp = read();
ar_d_Num1[i] = d_Tmp - i + 1;
ar_d_Num2[i] = d_Tmp - d_N + i;
}
int d_Pos1 = 1, d_Pos2 = d_N;
while (ar_d_Num1[d_Pos1] >= 0 && d_Pos1 <= d_N) d_Pos1++;
while (ar_d_Num2[d_Pos2] >= 0 && d_Pos2 >= 1) d_Pos2--;
if (d_Pos1 > d_N || d_Pos2 < 1) return -1;
return d_Pos1 - d_Pos2 >= 2;
}
int main() {
for (register int i = 1, I = read(); i <= I; i++)
if (alw())
print("Yes\n");
else
print("No\n");
output();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
long long int a[n];
int ind1 = -1;
int ind2 = -1;
int ans = 1;
for (int i = 0; i < n; i++) cin >> a[i];
for (int i = 0; i < n; i++) {
if (a[i] < i) {
ind1 = i;
break;
}
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] < n - i - 1) {
ind2 = i;
break;
}
}
if ((ind1 == -1 || ind2 == -1) || ind2 + 1 < ind1)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int md = 1e9 + 7;
const int MX = 2e5 + 5;
const long long INF = 1e18;
const long double PI = 4 * atan((long double)1);
long long power(long long a, long long n) {
long long res = 1;
while (n) {
if (n % 2) res *= a;
a *= a;
n /= 2;
}
return res;
}
long long abst(long long a) { return ((a < 0) ? (-1 * a) : (a)); }
int main() {
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
int arr[n];
for (int i = 0; i < n; i++) cin >> arr[i];
int f = 0, p = 1;
int prev = -1;
for (int i = 0; i < n; i++) {
if (f == 0) {
if (arr[i] >= (prev + 1))
prev++;
else {
if (prev > (n - i - 1)) {
prev = n - i - 1;
f = 1;
if (arr[i] < prev) {
p = 0;
break;
}
} else {
p = 0;
break;
}
}
} else {
prev = prev - 1;
if (arr[i] < prev) {
p = 0;
break;
}
}
}
if (p)
cout << "Yes\n";
else {
prev = -1;
p = 1;
f = 0;
for (int i = n - 1; i >= 0; i--) {
if (f == 0) {
if (arr[i] >= (prev + 1))
prev++;
else {
if (prev > (i)) {
prev = i;
f = 1;
if (arr[i] < prev) {
p = 0;
break;
}
} else {
p = 0;
break;
}
}
} else {
prev = prev - 1;
if (arr[i] < prev) {
p = 0;
break;
}
}
}
if (p)
cout << "Yes\n";
else
cout << "No\n";
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int a[300010];
int main() {
int i, j, k, n, m, x, y, z, t;
scanf("%d", &t);
while (t--) {
scanf("%d", &n);
for (i = 0; i < n; i++) {
scanf("%d", &a[i]);
}
for (i = 0; i < n; i++) {
if (a[i] < i) {
break;
}
}
i--;
for (j = n - 1; j >= 0; j--) {
if (a[j] < n - j - 1) {
break;
}
}
j++;
if (i >= j) {
printf("Yes\n");
} else {
printf("No\n");
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int T, N;
cin >> T;
while (T--) {
cin >> N;
int pr = -1, a = -1, k;
bool b = true;
int i = 0;
for (i = 0; i < N; i++) {
pr = a;
cin >> a;
if (a < i) break;
}
if (i < N && (pr <= (N - 1 - i) || a < (N - 1 - i))) {
b = false;
}
i++;
for (; i < N; i++) {
cin >> a;
if (b && a < N - 1 - i) {
b = false;
}
}
if (b)
cout << "YES" << endl;
else
cout << "NO" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
char s[3005];
int a[300005];
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i];
int l = n, r = 0;
for (int i = 1; i <= n; i++) {
if (a[i] >= i - 1)
r++;
else
break;
}
for (int i = n; i >= 1; i--) {
if (a[i] >= n - i)
l--;
else
break;
}
if (l < r)
cout << "Yes\n";
else
cout << "No" << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[]) {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> v(n);
for (int i = 0; i < n; i++) {
cin >> v[i];
}
int val = 0;
int i = 0;
while (i < n && v[i] >= i) {
i++;
}
if (i == n) {
cout << "Yes" << endl;
continue;
}
if (v[i] == v[i - 1]) {
val = v[i] - 1;
} else {
val = v[i];
}
if (val == -1) {
cout << "No" << endl;
continue;
}
i++;
while (i < n) {
if (v[i] >= val) {
val = val - 1;
} else {
val = v[i];
}
if (val == -1) {
break;
}
i++;
}
if (val >= 0 && i == n) {
cout << "Yes" << endl;
} else {
cout << "No" << endl;
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main(void) {
ios::sync_with_stdio(false);
cin.tie(NULL);
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long ar[n];
for (__typeof(n) i = (0) - ((0) > (n)); i != (n) - ((0) > (n));
i += 1 - 2 * ((0) > (n)))
cin >> ar[i];
long long pre[n], suf[n];
long long flag = 0;
pre[0] = 1;
suf[n - 1] = 1;
for (__typeof(n) i = (1) - ((1) > (n)); i != (n) - ((1) > (n));
i += 1 - 2 * ((1) > (n))) {
pre[i] = (pre[i - 1] && (ar[i] >= i));
}
for (long long i = n - 2; i >= 0; i--)
suf[i] = (suf[i + 1] && (ar[i] >= (n - 1 - i)));
for (__typeof(n) i = (0) - ((0) > (n)); i != (n) - ((0) > (n));
i += 1 - 2 * ((0) > (n))) {
if (pre[i] == 1 && suf[i] == 1) {
cout << "Yes" << '\n';
flag = 1;
break;
}
}
if (flag == 0) {
cout << "No" << '\n';
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 5;
const int mod = 1e9 + 7;
const int INF = 0x3f3f3f3f;
inline long long gcd(long long a, long long b) {
if (b == 0)
return a;
else
return gcd(b, a % b);
}
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
inline long long lowbit(long long x) { return (x & -x); }
inline long long kissme(long long x, long long y) {
long long res = 1;
if (x == 0) return 1;
if (x == 1) return y;
res = kissme(x / 2, y);
res = res * res % mod;
if (x % 2 == 1) res = res * y % mod;
return res;
}
void read(int &x) {
int f = 1;
x = 0;
char s = getchar();
while (s < '0' || s > '9') {
if (s == '-') f = -1;
s = getchar();
}
while (s >= '0' && s <= '9') {
x = x * 10 + s - '0';
s = getchar();
}
x *= f;
}
void print(int x) {
if (x < 0) putchar('-'), x = -x;
if (x > 9) print(x / 10);
putchar(x % 10 + '0');
}
int T, n, x[N];
bool f[N][2];
void solve() {
for (int i = 0; i < n + 2; i++) f[i][0] = f[i][1] = false;
f[0][0] = true;
f[n + 1][1] = true;
for (int i = 1; i <= n; i++) {
if (x[i] >= i - 1 && f[i - 1][0]) {
f[i][0] = true;
}
}
for (int i = n; i >= 1; i--) {
if (x[i] >= n - i && f[i + 1][1]) {
f[i][1] = true;
}
}
for (int i = 1; i <= n; i++) {
if (f[i][0] && f[i][1]) {
cout << "Yes\n";
return;
}
}
cout << "No\n";
return;
}
signed main() {
std::ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
;
cin >> T;
while (T--) {
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> x[i];
}
solve();
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int a[300010];
int b[300010];
int main() {
int t;
scanf("%d", &t);
while (t--) {
int n;
scanf("%d", &n);
int maxx = 0;
int maxxp = 0;
for (int i = 1; i <= n; i++) {
scanf("%d", &a[i]);
b[n - i + 1] = a[i];
}
int len1 = 0, len2 = 0;
while (len1 < n && a[len1 + 1] >= len1) ++len1;
while (len2 < n && b[len2 + 1] >= len2) ++len2;
if (len1 + len2 >= n + 1)
puts("Yes");
else
puts("No");
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long arr[n];
for (long long i = 0; i < n; i++) cin >> arr[i];
long long pr = -1, sf = n;
long long count = n - 1;
for (long long i = 0; i < n; i++) {
if (arr[i] < i) break;
pr = i;
}
for (long long i = n - 1; i > -1; i--) {
if (arr[i] < n - 1 - i) break;
sf = i;
}
if (sf <= pr)
cout << "Yes"
<< "\n";
else
cout << "No"
<< "\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const long long N = 300010, M = 10000005;
long long t, n, a[N], f[N], b[N], fs[N], bs[N], B, F;
int solve() {
scanf("%lld", &t);
while (t--) {
scanf("%lld", &n);
bool pos = 0;
B = 0, F = 0;
for (int i = 0; i < n; i++) {
scanf("%lld", &a[i]);
f[i] = 0, b[i] = 0;
if (a[i] < i) f[i] = 1;
if (a[i] < n - 1 - i) b[i] = 1;
B += b[i];
}
for (int i = 0; i < n; i++) {
F += f[i];
bs[i] = B;
fs[i] = F;
B -= b[i];
}
for (int i = 0; i < n; i++) {
long long x = 0, y = 0;
if (i - 1 >= 0) x = fs[i - 1];
if (i + 1 < n) y = bs[i + 1];
if (x == 0 && y == 0 && a[i] >= i && a[i] >= n - i - 1) {
pos = 1;
break;
}
}
if (pos)
printf("Yes\n");
else
printf("No\n");
}
return 0;
}
int main() {
int ret = solve();
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) cin >> a[i];
int maxl = 1, maxr = 1;
for (int i = 1; i < n; i++)
if (a[i] >= i)
maxl++;
else
break;
for (int i = n - 2; i >= 0; i--)
if (a[i] >= n - 1 - i)
maxr++;
else
break;
if (maxl + maxr > n)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
long long int t;
cin >> t;
while (t--) {
long long int n;
cin >> n;
long long int a[n];
for (int i = 0; i < n; ++i) cin >> a[i];
long long int j = 0, k = 0, z = -1, x = n;
for (int i = 0; i < n; ++i) {
if (a[i] >= j) {
j++;
z = i;
} else
break;
}
for (int i = n - 1; i >= 0; --i) {
if (a[i] >= k) {
k++;
x = i;
} else
break;
}
if (z >= x) {
cout << "Yes\n";
} else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int t, n;
cin >> t;
while (t--) {
cin >> n;
long long a[n];
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int l = 0, r = n - 1;
for (int i = 0; i < n; i++) {
if (a[i] >= i)
l = i;
else
break;
}
for (int j = n - 1; j >= 0; j--) {
if (a[j] >= n - 1 - j)
r = j;
else
break;
}
if (l >= r)
cout << "YES";
else
cout << "NO";
cout << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
bool p[100001] = {false};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
long long int t;
cin >> t;
while (t--) {
long long int n;
cin >> n;
long long int a[n], s = n, p = 0;
for (long long int i = 0; i < n; i++) cin >> a[i];
for (long long int i = 0; i < n; i++) {
if (a[i] < i) {
s = i - 1;
break;
}
}
for (long long int i = n - 1, j = -1; i >= 0; i--) {
if (a[i] < ++j) {
p = i + 1;
break;
}
}
if (s < p) {
cout << "No" << endl;
continue;
}
cout << "Yes" << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
long long T, n;
long long a[300005], b[300005];
void C() {
memset(a, 0, sizeof(long long) * (n + 1));
memset(b, 0, sizeof(long long) * (n + 1));
}
int main() {
cin >> T;
while (T--) {
C();
cin >> n;
if (n % 2 == 1) {
for (int i = 1; i <= n; ++i) cin >> a[i];
long long h = 1, t = n, cnt = -1;
while (1) {
if (h == t) {
b[h] = ++cnt;
break;
}
b[h] = b[t] = ++cnt;
h++, t--;
}
bool ok = 0;
for (int i = 1; i <= n; ++i) {
if (a[i] < b[i]) {
puts("No");
ok = 1;
break;
}
}
if (ok == 0) puts("Yes");
} else {
int sb;
for (int i = 1; i <= n; ++i) cin >> a[i];
long long h = 1, t = n, cnt = -1;
while (1) {
if (h + 1 == t) {
b[h] = b[t] = ++cnt;
sb = h;
b[h]++;
break;
}
b[h] = b[t] = ++cnt;
h++, t--;
}
bool ok = 0;
for (int i = 1; i <= n; ++i) {
if (a[i] < b[i]) {
ok = 1;
break;
}
}
if (ok == 0) {
puts("Yes");
continue;
}
b[sb]--;
b[sb + 1]++;
ok = 0;
for (int i = 1; i <= n; ++i) {
if (a[i] < b[i]) {
puts("No");
ok = 1;
break;
}
}
if (ok == 0) puts("Yes");
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int t;
cin >> t;
for (int it = 0; it < t; ++it) {
int n;
cin >> n;
vector<int> v(n, 0);
for (auto& x : v) cin >> x;
vector<int> kek(n, 0);
if (n % 2 == 1) {
for (int i = 0; i <= n / 2; i++) {
kek[i] = i;
}
kek[n / 2 + 1] = n / 2 + 1;
for (int i = 0; i <= n / 2; i++) {
kek[n - 1 - i] = i;
}
bool yes = true;
for (int i = 0; i < n; i++) {
if (v[i] < kek[i]) yes = false;
}
if (yes)
cout << "Yes\n";
else
cout << "No\n";
} else {
for (int i = 0; i < n / 2; i++) {
kek[i] = i;
}
kek[n / 2] = n / 2;
for (int i = n / 2 + 1; i < n; i++) {
kek[i] = n - 1 - i;
}
bool yes = true;
for (int i = 0; i < n; i++) {
if (v[i] < kek[i]) yes = false;
}
if (yes) {
cout << "Yes\n";
continue;
}
reverse(kek.begin(), kek.end());
yes = true;
for (int i = 0; i < n; i++) {
if (v[i] < kek[i]) yes = false;
}
if (yes) {
cout << "Yes\n";
continue;
}
cout << "No\n";
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
long long int t;
cin >> t;
while (t--) {
int n;
cin >> n;
long long int a[n];
for (int i = 0; i < n; i++) cin >> a[i];
long long int flag = 0ll;
bool ok = true;
long long int start = 0;
for (int i = 0; i < n; i++) {
if (a[i] < i) {
break;
}
start = i;
}
flag = a[start];
for (int i = start + 1; i < n; i++) {
flag = min(a[i], flag - 1);
if (flag < 0) {
ok = false;
break;
}
}
if (!ok) {
cout << "NO\n";
} else {
cout << "YES\n";
}
}
}
|
#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 1;
const int MOD = 1e9 + 7;
const int base = 257;
const int M = 1e6 + 1;
const int INFI = 1e8;
long long Hash[M], po[M];
long long gethash(long long l, long long r) {
return ((Hash[r] - Hash[l - 1] * po[r - l + 1] + MOD * MOD) % MOD);
}
void precomputehashing() {
po[0] = 1;
for (int i = 1; i <= M; i++) po[i] = (po[i - 1] * base) % MOD;
string s;
s = " " + s;
for (int i = 1; i <= s.size() - 1; i++)
Hash[i] = (Hash[i - 1] * base + s[i] - '*' + 1) % MOD;
}
long long fac[N], ifac[N];
long long PowerMod(long long a, long long n) {
long long ret = 1;
while (n) {
if (n & 1) {
ret *= a;
ret %= MOD;
}
a *= a;
a %= MOD;
n /= 2;
}
return ret;
}
void precomputecombinatoris() {
int i;
fac[0] = 1;
for (i = 1; i < N; i++) {
fac[i] = (i * fac[i - 1]) % MOD;
}
ifac[N - 1] = PowerMod(fac[N - 1], MOD - 2);
for (i = N - 2; i >= 0; i--) {
ifac[i] = ((i + 1) * ifac[i + 1]) % MOD;
}
}
long long C(int r, int n) {
long long ret = fac[n];
ret *= ifac[r];
ret %= MOD;
ret *= ifac[n - r];
ret %= MOD;
return ret;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
int a[N];
bool check = 0;
for (int i = 0; i <= n - 1; i++) {
cin >> a[i];
}
bool res = 1;
for (int i = 0; i <= n - 1; i++) {
if (a[i] < i) {
if (a[i] == a[i - 1]) a[i]--;
int cnt = 0;
for (int j = n - 1; j >= i; j--) {
if (a[j] < cnt || cnt > a[i]) {
res = 0;
break;
} else {
cnt++;
}
}
break;
}
}
if (res) {
cout << "YES"
<< "\n";
} else {
cout << "NO"
<< "\n";
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr), cout.tie(nullptr);
int tc;
cin >> tc;
while (tc--) {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < (int)(n); i++) cin >> a[i];
int preItr = -1, suffixItr = n;
for (int i = 0; i < n; i++) {
if (a[i] < i) break;
preItr = i;
}
for (int i = n - 1; i >= 0; i--) {
if (a[i] < (n - 1) - i) break;
suffixItr = i;
}
if (suffixItr <= preItr)
cout << "Yes" << '\n';
else
cout << "No" << '\n';
}
}
|
#include <bits/stdc++.h>
using namespace std;
vector<map<int, int>> adj;
vector<vector<int>> ver;
vector<bool> storage;
void Solve() {
int n;
cin >> n;
vector<int> vec(n);
int pr = n;
for (int i = 0; i < n; ++i) {
cin >> vec[i];
if (pr == n && vec[i] < i) pr = i;
}
--pr;
int sf = -1;
for (int i = n - 1; i >= 0; --i) {
if (vec[i] < n - i - 1) {
sf = i;
break;
}
}
++sf;
if (sf <= pr)
cout << "Yes\n";
else
cout << "No\n";
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int t;
cin >> t;
while (t--) Solve();
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
int T0;
cin >> T0;
for (int _ = 0; _ < T0; _++) {
int n;
cin >> n;
int a[n];
for (int i = 0; i < n; i++) {
cin >> a[i];
}
bool f = 1;
for (int i = 0; f && i < (n + 1) / 2; i++) {
if (a[i] < i) f = 0;
}
for (int i = (n + 1) / 2; f && i < n; i++) {
if (a[i] < n - 1 - i) f = 0;
}
if (!(n % 2) && a[n / 2 - 1] == a[(n) / 2] && a[n / 2] == n / 2 - 1) f = 0;
if (f)
cout << "Yes\n";
else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
long long arr[300000];
long long temp[300000];
int main() {
int q;
cin >> q;
while (q--) {
int n;
cin >> n;
for (int i = 0; i < n; i++) {
cin >> arr[i];
temp[i] = arr[i];
}
int st = 0;
int endIdx1 = -1;
for (int i = 0; i < n; i++) {
if (arr[i] >= st) {
st++;
endIdx1 = i;
} else {
break;
}
}
if (endIdx1 == n - 1) {
cout << "Yes" << endl;
continue;
}
st = 0;
int endIdx = n;
for (int i = n - 1; i >= 0; i--) {
if (arr[i] >= st) {
st++;
endIdx = i;
} else {
break;
}
}
if (endIdx == 0) {
cout << "Yes" << endl;
continue;
}
if (endIdx1 >= endIdx) {
cout << "Yes" << endl;
} else {
cout << "No" << endl;
}
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
inline int re() {
int x = 0, f = 1;
char ch = getchar();
while (ch < '0' || ch > '9') {
if (ch == '-') f = -1;
ch = getchar();
}
while (ch >= '0' && ch <= '9') {
x = (x << 3) + (x << 1) + (ch ^ 48);
ch = getchar();
}
return x * f;
}
int z[333333], y[333333];
int a[333333];
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
z[0] = 1;
for (int i = 1; i <= n; i++) {
a[i] = re();
if (a[i] >= i - 1 && z[i - 1])
z[i] = 1;
else
z[i] = 0;
}
y[n + 1] = 1;
int f = 0;
for (int i = n; i >= 1; i--) {
if (a[i] >= n - i && y[i + 1]) {
y[i] = 1;
} else
y[i] = 0;
if (y[i] && z[i]) {
f = 1;
break;
}
}
if (f == 1)
puts("Yes");
else
puts("No");
}
}
|
#include <bits/stdc++.h>
using namespace std;
const int M = 1e9 + 7;
const int inf = 1e9 + 5;
const int nax = 1e5 + 10;
void solve() {
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
for (int i = 0; i < n; i++) {
if (a[i] < i) {
for (int j = i; j < n; j++) {
if (a[j] >= a[j - 1] && a[j - 1] != 0)
a[j] = a[j - 1] - 1;
else if (a[j] >= a[j - 1] && a[j - 1] == 0) {
cout << "No";
return;
}
}
break;
}
}
cout << "Yes";
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
long long T;
cin >> T;
while (T--) {
solve();
cout << "\n";
}
return 0;
}
|
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
inline bool setmin(int &x, int y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(int &x, int y) { return (y > x) ? x = y, 1 : 0; }
inline bool setmin(long long &x, long long y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(long long &x, long long y) { return (y > x) ? x = y, 1 : 0; }
using namespace std;
int n;
int a[300000];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.precision(20);
int T;
cin >> T;
while (T--) {
cin >> n;
for (int i = (0); i < (n); ++i) cin >> a[i];
int f = 1;
int i = 1;
while (i < n && a[i] >= i) i++;
if (i) i--;
int h = n - i - 1;
while (i < n && a[i] >= h) i++, h--;
if (i == n)
cout << "Yes\n";
else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
const long long int MaxN = 300005;
const long long int mod = 1e9 + 7;
const float pi = 3.1415926535897932384626433832795028;
long long int mcd(long long int a, long long int b) {
if (a == 0) return b;
return mcd(b % a, a);
}
int arr[MaxN];
void solve() {
int N, i, j, p, q;
cin >> N;
for (i = 1; i <= N; i++) {
cin >> arr[i];
}
p = 0, q = N + 1;
for (i = 1; i <= N; i++) {
if (arr[i] >= i - 1) {
p = i;
} else
break;
}
for (i = N; i > 0; i--) {
if (arr[i] >= N - i) {
q = i;
} else
break;
}
if (p >= q)
cout << "Yes\n";
else
cout << "No\n";
}
int main() {
long long int t, i;
cin >> t;
for (i = 1; i <= t; i++) {
solve();
}
}
|
#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
long long t;
cin >> t;
while (t--) {
long long n;
cin >> n;
long long ar[n];
for (long long i = 0; i < n; i++) cin >> ar[i];
long long ans = 0;
long long begin = 0, k = 0;
while (begin < n && ar[begin] >= begin) begin++;
if (begin == n) ans = 1;
begin = n - 1;
while (begin > 0 && ar[begin] >= k) {
begin--;
k++;
}
if (k == n) ans = 1;
long long left = 0, right = n - 1;
k = 0;
while (ar[left] >= left) left++;
left--;
while (ar[right] >= k) {
right--;
k++;
}
right++;
if (left >= right) ans = 1;
if (ans == 1)
cout << "Yes" << endl;
else
cout << "No" << endl;
}
}
|
#include <bits/stdc++.h>
using namespace std;
const int inf = (int)1e9 + 5;
int n, a[(int)1e6 + 5];
int main(void) {
ios_base::sync_with_stdio(false), cin.tie(nullptr);
int tc;
cin >> tc;
while (tc--) {
cin >> n;
int i;
for (i = 0; i < n; ++i) {
cin >> a[i];
}
int l = n, r = n;
for (i = 0; i < n; ++i) {
if (a[i] < i) {
l = i;
break;
}
}
reverse(a, a + n);
for (i = 0; i < n; ++i) {
if (a[i] < i) {
r = i;
break;
}
}
if (l + r > n)
cout << "Yes\n";
else
cout << "No\n";
}
return 0;
}
|
#include <bits/stdc++.h>
using namespace std;
int solve() {
long long n, r = 0;
cin >> n;
long long l = n;
vector<long long int> a(n);
for (long long int i = 0; i < n; i++) cin >> a[i];
for (long long int i = 0; i < n; i++)
if (a[i] >= i)
continue;
else {
l = i - 1;
break;
}
for (long long int i = n - 1; i > -1; i--)
if (a[i] >= n - 1 - i)
continue;
else {
r = i + 1;
break;
}
cout << (l >= r ? "YES\n" : "NO\n");
return 0;
}
int main() {
auto start = chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
long long test_cases = 1;
cin >> test_cases;
while (test_cases--) solve();
auto stop = chrono::high_resolution_clock::now();
auto duration = chrono::duration_cast<chrono::milliseconds>(stop - start);
}
|
#include <bits/stdc++.h>
const long long MOD = 1000 * 1000 * 1000 + 7;
using namespace std;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int T;
cin >> T;
while (T--) {
long long N;
cin >> N;
long long A[N];
long long flag = 0;
for (long long i = 0; i < N; i++) {
cin >> A[i];
}
if (N % 2 != 0) {
for (long long i = 0; i < N; i++) {
if (A[i] < min(i, N - i - 1)) {
flag = 1;
break;
}
}
} else {
for (long long i = 0; i < N; i++) {
if (A[i] < min(i, N - i - 1)) {
flag = 1;
break;
}
if (A[(N / 2) - 1] == A[N / 2] && A[N / 2] == (N / 2) - 1) {
flag = 1;
break;
}
}
}
if (flag == 1)
cout << "No" << '\n';
else
cout << "Yes" << '\n';
}
return 0;
}
|
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