Submission #1243808

#	Time	Username	Problem	Language	Result	Execution time	Memory
1243808		lopkus	Trains (BOI24_trains)	C++20	21 / 100	2095 ms	2120 KiB

Main

#include <bits/stdc++.h>

#define int long long

int mod = 1e9 + 7;

int add(int x, int y) {
  x += y;
  x %= mod;
  return x;
}

signed main() {
  int n;
  std::cin >> n;
  std::vector<int> d(n + 1), x(n + 1);
  for(int i = 1; i <= n; i++) {
    std::cin >> d[i] >> x[i];
  }
  std::vector<int> dp(n + 1, 0);
  dp[1] = 1;
  for(int i = 2; i <= n; i++) {
    for(int j = i - 1; j >= 1; j--) {
      if(d[j] == 0) {
        continue;
      }
      if((i - j) % d[j] == 0) {
        int t = (i - j) / d[j];
        if(t <= x[j]) {
          dp[i] = add(dp[i], dp[j]);
        }
      }
    }
  }
  int ans = 0;
  for(int i = 1; i <= n; i++) {
    ans = add(ans, dp[i]);
  }
  std::cout << ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 13 / 13
• Subtask 3: 0 / 16
• Subtask 4: 0 / 34
• Subtask 5: 0 / 29