File size: 2,406 Bytes
14c9c2b | 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 | #include <bits/stdc++.h>
using namespace std;
int ask(const vector<int>& q) {
cout << 0;
for (int x : q) cout << ' ' << x;
cout << endl;
int res;
cin >> res;
return res;
}
void guess(const vector<int>& p) {
cout << 1;
for (int x : p) cout << ' ' << x;
cout << endl;
exit(0);
}
int main() {
int n;
cin >> n;
if (n == 1) {
guess({1});
}
vector<int> pos(n + 1, -1); // pos[value] = position (1-indexed)
vector<int> unknown;
for (int i = 1; i <= n; ++i) unknown.push_back(i);
// Step 1: find positions of 1 and 2
for (int i = 1; i <= n && (pos[1] == -1 || pos[2] == -1); ++i) {
vector<int> q(n);
for (int j = 1; j <= n; ++j) {
if (j == i) q[j-1] = 1;
else q[j-1] = 2;
}
int r = ask(q);
if (r == 2) pos[1] = i;
else if (r == 0) pos[2] = i;
}
// Remove found positions from unknown
unknown.clear();
for (int i = 1; i <= n; ++i) {
if (i != pos[1] && i != pos[2]) unknown.push_back(i);
}
// Step 2: find positions for values 3..n using binary search
for (int v = 3; v <= n; ++v) {
int m = unknown.size();
if (m == 1) {
pos[v] = unknown[0];
break;
}
int lo = 0, hi = m - 1;
while (lo < hi) {
int mid = (lo + hi) / 2;
vector<int> q(n);
// set known positions
for (int w = 1; w < v; ++w) {
q[pos[w] - 1] = w;
}
// set first half of unknown to v
for (int i = lo; i <= mid; ++i) {
int idx = unknown[i];
q[idx - 1] = v;
}
// set the rest of unknown to 1 (already placed, so no match)
for (int i = mid + 1; i < m; ++i) {
int idx = unknown[i];
q[idx - 1] = 1;
}
int r = ask(q);
if (r == v) { // pos[v] is in the first half
hi = mid;
} else { // r == v-1, pos[v] is in the second half
lo = mid + 1;
}
}
pos[v] = unknown[lo];
unknown.erase(unknown.begin() + lo);
}
// Build the permutation from the positions
vector<int> ans(n);
for (int v = 1; v <= n; ++v) {
ans[pos[v] - 1] = v;
}
guess(ans);
return 0;
} |