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Submission #225468

# Submission time Handle Problem Language Result Execution time Memory
225468 2020-04-20T15:32:56 Z brcode Kangaroo (CEOI16_kangaroo) C++14
6 / 100
 5 ms 384 KB 
#include <iostream>
#include <bits/stdc++.h>

using namespace std;
const int MAXN = 5e3+5;
const long long MOD = 1e9+7;
int dp[MAXN][MAXN];
int n,a,b;
int main(){
    cin>>n>>a>>b;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(i==1 && j==1){
                dp[i][j] = 1;
                continue;
            }
            if(i==a||i==b){
                dp[i][j] = dp[i-1][j-1]+dp[i-1][j];
                dp[i][j]%=MOD;
            }else{
                dp[i][j] = dp[i-1][j+1]*j;
                dp[i][j]%=MOD;
                dp[i][j]+=dp[i-1][j-1]*(j-(i>a)-(i>b));
                dp[i][j]%=MOD;
            }
        }
    }
    cout<<dp[n][1]<<endl;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Incorrect 4 ms 384 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Incorrect 4 ms 384 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Incorrect 4 ms 384 KB Output isn't correct
4 Halted 0 ms 0 KB -