Submission #71257145

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Source Code Expand

// BLuemoon_
#include <bits/stdc++.h>

using namespace std;
using LL = long long;
using DB = double;

const int kMaxN = 505;
const LL kP = 998244353;

LL T = 1, n, k, m, a[kMaxN], ans, c[kMaxN][kMaxN], p[kMaxN][kMaxN * kMaxN], dp[kMaxN];

void pr(bool pr) { cout << (pr ? "Yes" : "No") << '\n'; }

int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  for (; T; T--, ans = 0) {
    cin >> n >> m;
    for (int i = 0; i < kMaxN; i++) {
      c[i][0] = 1;
      for (int j = 1; j <= i; j++) {
        c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % kP;
      }
      p[i][0] = 1;
      for (int j = 1; j <= kMaxN * kMaxN; j++) {
        p[i][j] = p[i][j - 1] * i % kP;
      }
    }
    ans = (n - m - 1) * p[m][n * (n - 1) / 2] % kP;
    for (int i = 1; i <= m; i++) {
      for (int j = 1; j <= n; j++) {
        dp[j] = p[m][j * (j - 1) / 2];
        for (int k = 1; k < j; k++) {
          (dp[j] -= (dp[k] * c[j - 1][k - 1] % kP * p[m - i][k * (j - k)] % kP * p[m][(j - k) * (j - k - 1) / 2] % kP) - kP) %= kP;
        }
        (ans += c[n][j] * dp[j] % kP * p[m - i][j * (n - j)] % kP * p[m][(n - j) * (n - j - 1) / 2] % kP) %= kP;
      }
    }
    cout << ans << '\n';
  }
  return 0;
}

Submission Info

Compile Error

Main.cpp: In function ‘int main()’:
Main.cpp:26:17: warning: iteration 255024 invokes undefined behavior [-Waggressive-loop-optimizations]
   26 |         p[i][j] = p[i][j - 1] * i % kP;
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:25:25: note: within this loop
   25 |       for (int j = 1; j <= kMaxN * kMaxN; j++) {
      |                       ~~^~~~~~~~~~~~~~~~

Judge Result