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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#611521 | #8939. Permutation | UESTC_OldEastWest | WA | 234ms | 331360kb | C++17 | 2.1kb | 2024-10-04 21:19:18 | 2024-10-04 21:19:19 |
Judging History
answer
#include <bits/stdc++.h>
const int N = 1e6 + 5;
const int M = 31;
const int INF = 1e9;
const double eps = 1e-8;
std::vector<std::vector<int> > dp, f;
void prep() {
dp = f = std::vector<std::vector<int> > (N, std::vector<int> (M));
std::function<int(int, int)> DFS = [&](int n, int m) {
if (n == 1) return 0;
if (m == 0) return INF;
if (dp[n][m]) return dp[n][m];
dp[n][m] = INF;
int mid = n >> 1;
for (int i = mid; i < std::min(n, mid + 2); ++i) {
int new_val = std::max(DFS(i, m - 1), DFS(n - i, m - 1) + n - i) + i;
if (new_val < dp[n][m]) f[n][m] = i, dp[n][m] = new_val;
}
return dp[n][m];
};
for (int i = 2; i < N; ++i) {
int k = int(1.5 * log(i) / log(2) + 1.0);
for (int j = std::max(0, k - 1); j <= k; ++j) DFS(i, j);
// if (DFS(i, k) > 2 * i) std::cout << '!';
// if (i % 1000 == 0) std::cout << i << ' ' << DFS(i, k) << '\n';
}
// std::cout << "Finished." << std::endl;
}
void charming() {
int n; std::cin >> n;
std::function<int(int, int)> Send = [&](int l, int r) {
if (l == r) return -1;
std::cout << "? " << l << ' ' << r << '\n';
std::cout.flush();
int rcv; std::cin >> rcv;
return rcv;
};
std::function<void(int)> Answer = [&](int x) {
std::cout << "! " << x << '\n';
std::cout.flush();
};
int remain = int(1.5 * (log(n) / log(2)) + 1.0 + eps);
// std::cout << remain << '\n';
int l = 1, r = n, p = -1;
while (l < r) {
if (p == -1) p = Send(l, r), --remain;
if (l + 1 == r) {
if (p == l) ++l;
break;
}
int ask_len = f[r - l + 1][remain];
if (l + ask_len - 1 >= p) {
int q = Send(l, l + ask_len - 1); --remain;
if (q == p) r = l + ask_len - 1;
else l = l + ask_len, p = -1;
}
else {
int q = Send(r - ask_len + 1, r); --remain;
if (q == p) l = r - ask_len + 1;
else r = r - ask_len, p = -1;
}
}
Answer(l);
}
signed main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(NULL);
std::cout.tie(NULL);
prep();
int t; std::cin >> t;
while (t--) charming();
return 0;
}
Details
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Test #1:
score: 0
Wrong Answer
time: 234ms
memory: 331360kb
input:
3 5 3 2 5 6 6 5 3
output:
? 1 5 ? 1 3 ? 4 5 ! 4 ? 1 6 ? 4 6 ? 1 3 ? 4 3
result:
wrong answer Integer 3 violates the range [5, 6] (test case 2)