File size: 2,476 Bytes
1fd0050 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | #include <bits/stdc++.h>
using namespace std;
static const int QUERY_LIMIT = 50000;
long long used_queries = 0;
long long do_query(int x, int y) {
cout << "QUERY " << x << " " << y << endl;
cout.flush();
long long v;
if (!(cin >> v)) {
exit(0);
}
used_queries++;
return v;
}
[[noreturn]] void done(long long ans) {
cout << "DONE " << ans << endl;
cout.flush();
exit(0);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
long long k;
if (!(cin >> n >> k)) {
return 0;
}
long long total = 1LL * n * n;
long long k_from_end = total - k + 1;
struct Node {
long long v;
int i, j;
bool operator<(const Node& other) const {
return v > other.v; // min-heap
}
};
struct NodeMax {
long long v;
int i, j;
bool operator<(const NodeMax& other) const {
return v < other.v; // max-heap
}
};
if (k <= k_from_end) {
priority_queue<Node> pq;
vector<int> ptr(n + 1, 1);
// Initialize heads of all rows (column 1)
for (int i = 1; i <= n; ++i) {
long long v = do_query(i, 1);
pq.push({v, i, 1});
}
long long cnt = 0;
long long ans = 0;
while (!pq.empty()) {
Node cur = pq.top(); pq.pop();
cnt++;
if (cnt == k) {
ans = cur.v;
done(ans);
}
int i = cur.i;
int j = cur.j;
if (j + 1 <= n) {
long long v = do_query(i, j + 1);
pq.push({v, i, j + 1});
}
}
} else {
priority_queue<NodeMax> pq;
vector<int> ptr(n + 1, n);
// Initialize tails of all rows (column n)
for (int i = 1; i <= n; ++i) {
long long v = do_query(i, n);
pq.push({v, i, n});
}
long long target = k_from_end;
long long cnt = 0;
long long ans = 0;
while (!pq.empty()) {
NodeMax cur = pq.top(); pq.pop();
cnt++;
if (cnt == target) {
ans = cur.v;
done(ans);
}
int i = cur.i;
int j = cur.j;
if (j - 1 >= 1) {
long long v = do_query(i, j - 1);
pq.push({v, i, j - 1});
}
}
}
return 0;
} |