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Submission #474834

# Submission time Handle Problem Language Result Execution time Memory
474834 2021-09-20T03:25:19 Z ntabc05101 Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 40 ms 15948 KB 
#include<bits/stdc++.h>
using namespace std;

#define taskname "kangaroo"

const int mxN = 2000;
const int mod = 1e9 + 7;

int n, cs, cf;
int dp[mxN + 5][mxN + 5];

int main() {
  if (fopen(taskname".inp", "r")) {
    freopen(taskname".inp", "r", stdin);
    freopen(taskname".out", "w", stdout);
  }

  cin.tie(0)->sync_with_stdio(0);

  cin >> n >> cs >> cf;
  dp[1][1] = 1;
  for (int i = 2; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      if (i == cs || i == cf) {
        dp[i][j] = (dp[i - 1][j - 1] + dp[i - 1][j]) % mod;
      }
      else {
        dp[i][j] = 1ll * dp[i - 1][j + 1] * j % mod;
        (dp[i][j] += 1ll * dp[i - 1][j - 1] * (j - (i > cs) - (i > cf)) % mod) %= mod;
      }
    }
  }

  cout << dp[n][1] << "\n";

  return 0;
}

Compilation message

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:14:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     freopen(taskname".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen(taskname".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 448 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 444 KB Output is correct
11 Correct 1 ms 460 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 448 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 444 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1228 KB Output is correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 1 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1212 KB Output is correct
17 Correct 1 ms 1244 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 1 ms 1228 KB Output is correct
20 Correct 2 ms 1228 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 448 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 444 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1228 KB Output is correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 1 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1212 KB Output is correct
17 Correct 1 ms 1244 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 1 ms 1228 KB Output is correct
20 Correct 2 ms 1228 KB Output is correct
21 Correct 6 ms 4556 KB Output is correct
22 Correct 6 ms 4940 KB Output is correct
23 Correct 6 ms 5488 KB Output is correct
24 Correct 40 ms 15944 KB Output is correct
25 Correct 39 ms 15948 KB Output is correct
26 Correct 33 ms 15944 KB Output is correct
27 Correct 35 ms 15920 KB Output is correct
28 Correct 20 ms 11980 KB Output is correct