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Submission #237826

# Submission time Handle Problem Language Result Execution time Memory
237826 2020-06-08T23:51:55 Z thecodingwizard Kangaroo (CEOI16_kangaroo) C++11
0 / 100
 5 ms 384 KB 
#include <bits/stdc++.h>

using namespace std;

long long dp[2001][2001]; 

int main() {
    int n, cs, cf; cin >> n >> cs >> cf;

    for (int i = 0; i <= n;i++) for (int j = 0; j <= n; j++) dp[i][j] = 0;
    dp[1][1] = 1;
    for (int i = 2; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            if (i == cs || i == cf) {
                dp[i][j] = (dp[i-1][j-1] + dp[i-1][j])%1000000007;
            } else {
                int j2 = j-(i>cs)-(i>cf);
                dp[i][j] = (dp[i-1][j-1] + dp[i-1][j+1]*((j2+1)*j2%1000000007))%1000000007;
               // dp[i][j] = dp[i-1][j+1]*j + dp[i-1][j-1]*(j-(i>cs)-(i>cf));
            }
        }
    }
    //cout << dp[n][1] << endl;
    cout << dp[n][3] << endl;

    return 0;
}

Subtask #1
0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Incorrect 5 ms 384 KB Output isn't correct

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Incorrect 5 ms 384 KB Output isn't correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Incorrect 5 ms 384 KB Output isn't correct

Subtask #4
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Incorrect 5 ms 384 KB Output isn't correct