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Submission #307095

# Submission time Handle Problem Language Result Execution time Memory
307095 2020-09-27T03:08:06 Z two_sides Kangaroo (CEOI16_kangaroo) C++17
0 / 100
 1 ms 384 KB 
#include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
 
const int N = 2005;
const int MOD = 1e9 + 7;
 
int dp[N][N];
 
int madd(int x, int y) {
    if ((x += y) >= MOD)
        x -= MOD;
    return x;
}
 
int mmul(int x, int y) {
    return ll(x) * y % MOD;
}
 
int main() {
    cin.tie(0)->sync_with_stdio(0);
    int n, s, t; cin >> n >> s >> t;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= i; j++) {
            if (i == s || i == t)
                dp[i][j] = madd(dp[i - 1][j - 1], dp[i - 1][j]);
            else dp[i][j] = madd(mmul(dp[i - 1][j + 1], j),
            mmul(dp[i - 1][j - 1], j - (i > s) - (i > t)));
        }
    cout << dp[n][1] << '\n';
}

Subtask #1
0 / 6.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 49.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -