oj.uz

Submission #806989

# Submission time Handle Problem Language Result Execution time Memory
806989 2023-08-04T12:01:42 Z nonono Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 18 ms 22996 KB 
#include <bits/stdc++.h>
#define int long long
using namespace std;

const int mod = 1e9 + 7;
const int mxN = 2005;

int n, s, f;
int dp[mxN][mxN];

signed main() {
    #define taskname ""

    if(fopen(taskname".inp", "r")) {
        freopen(taskname".inp", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
    
    cin.tie(0)->sync_with_stdio(0);
    
    cin >> n >> s >> f;
    
    dp[1][1] = 1;
    for(int i = 1; i < n; i ++) {
        int x = (i + 1 >= s) + (i + 1 >= f);
        
        for(int j = 1; j <= i; j ++) {
            if(i + 1 == s || i + 1 == f) {
                dp[i + 1][j] += dp[i][j];
                dp[i + 1][j + 1] += dp[i][j];
                continue ;
            }
            
            (dp[i + 1][j + 1] += dp[i][j] * (j + 1 - x)) %= mod;
            (dp[i + 1][j - 1] += dp[i][j] * (j - 1)) %= mod;
        }
    }
    
    cout << dp[n][1] << "\n";
    return 0;
}

Compilation message

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:15:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:16:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 328 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 476 KB Output is correct
10 Correct 1 ms 468 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 340 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 476 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1236 KB Output is correct
13 Correct 1 ms 1108 KB Output is correct
14 Correct 1 ms 1236 KB Output is correct
15 Correct 1 ms 1236 KB Output is correct
16 Correct 1 ms 1224 KB Output is correct
17 Correct 1 ms 1236 KB Output is correct
18 Correct 1 ms 1108 KB Output is correct
19 Correct 1 ms 1236 KB Output is correct
20 Correct 2 ms 1236 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 476 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1236 KB Output is correct
13 Correct 1 ms 1108 KB Output is correct
14 Correct 1 ms 1236 KB Output is correct
15 Correct 1 ms 1236 KB Output is correct
16 Correct 1 ms 1224 KB Output is correct
17 Correct 1 ms 1236 KB Output is correct
18 Correct 1 ms 1108 KB Output is correct
19 Correct 1 ms 1236 KB Output is correct
20 Correct 2 ms 1236 KB Output is correct
21 Correct 5 ms 4564 KB Output is correct
22 Correct 4 ms 5076 KB Output is correct
23 Correct 4 ms 5580 KB Output is correct
24 Correct 16 ms 22996 KB Output is correct
25 Correct 18 ms 22960 KB Output is correct
26 Correct 18 ms 22976 KB Output is correct
27 Correct 18 ms 22808 KB Output is correct
28 Correct 12 ms 15096 KB Output is correct