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Submission #817127

# Submission time Handle Problem Language Result Execution time Memory
817127 2023-08-09T09:42:22 Z gun_gan Tents (JOI18_tents) C++17
100 / 100
 169 ms 70832 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int MX = 3005, mod = 1e9 + 7, inv = 5e8 + 4;

int H, W;
ll dp[MX][MX];

int main() {
      cin.tie(0); ios_base::sync_with_stdio(0);

      cin >> H >> W;

      dp[0][W] = 1;

      for(int i = 0; i < H; i++) {
            for(int a = 0; a <= W; a++) { 
                  dp[i + 1][a] += dp[i][a];
                  dp[i + 1][a] %= mod;

                  if(a - 1 >= 0) {
                        dp[i + 1][a - 1] += 1LL * dp[i][a] * a * 4 % mod;
                        dp[i + 1][a - 1] %= mod;
                  }

                  if(a - 2 >= 0) {
                        dp[i + 1][a - 2] += 1LL * dp[i][a] * a % mod * (a - 1) % mod * inv % mod;
                        dp[i + 1][a - 2] %= mod;
                  }

                  if(i + 2 <= H && a - 1 >= 0) {
                        dp[i + 2][a - 1] += 1LL * dp[i][a] * (H - i - 1) % mod * a % mod;
                        dp[i + 2][a - 1] %= mod;
                  }
            }
      }


      ll ans = 0;
      for(int a = 0; a < W; a++) {
            ans += dp[H][a];
            ans %= mod;
      }

      cout << ans << '\n';
      
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 468 KB Output is correct
4 Correct 1 ms 1108 KB Output is correct
5 Correct 1 ms 596 KB Output is correct
6 Correct 1 ms 1364 KB Output is correct
7 Correct 1 ms 724 KB Output is correct
8 Correct 1 ms 1364 KB Output is correct
9 Correct 1 ms 724 KB Output is correct
10 Correct 2 ms 1736 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 3 ms 2132 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 468 KB Output is correct
4 Correct 1 ms 1108 KB Output is correct
5 Correct 1 ms 596 KB Output is correct
6 Correct 1 ms 1364 KB Output is correct
7 Correct 1 ms 724 KB Output is correct
8 Correct 1 ms 1364 KB Output is correct
9 Correct 1 ms 724 KB Output is correct
10 Correct 2 ms 1736 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 3 ms 2132 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 5 ms 9684 KB Output is correct
15 Correct 110 ms 55116 KB Output is correct
16 Correct 8 ms 4048 KB Output is correct
17 Correct 25 ms 12776 KB Output is correct
18 Correct 33 ms 17004 KB Output is correct
19 Correct 134 ms 62992 KB Output is correct
20 Correct 104 ms 50808 KB Output is correct
21 Correct 69 ms 33684 KB Output is correct
22 Correct 71 ms 35472 KB Output is correct
23 Correct 43 ms 26956 KB Output is correct
24 Correct 169 ms 70832 KB Output is correct
25 Correct 130 ms 61132 KB Output is correct
26 Correct 147 ms 66576 KB Output is correct
27 Correct 162 ms 68992 KB Output is correct