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Submission #813182

# Submission time Handle Problem Language Result Execution time Memory
813182 2023-08-07T14:08:49 Z ttamx Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 15 ms 14100 KB 
#include<bits/stdc++.h>
 
using namespace std;
 
const int N=2005;
const int mod=1e9+7;
 
int n,s,e;
int dp[N][N];
 
int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n >> s >> e;
    dp[1][1]=1;
    int cnt=2;
    for(int i=1;i<=n;i++){
        if(i==s||i==e){
            for(int j=1;j<i;j++){
                dp[i][j+1]+=dp[i-1][j];
              	if(dp[i][j+1]>=mod)dp[i][j+1]-=mod;
                dp[i][j]+=dp[i-1][j];
              	if(dp[i][j]>=mod)dp[i][j]-=mod;
            }
            cnt--;
            continue;
        }
        for(int j=1;j<i;j++){
            dp[i][j+1]=(dp[i][j+1]+1ll*dp[i-1][j]*(cnt+j-1))%mod;
            dp[i][j-1]=(dp[i][j-1]+1ll*dp[i-1][j]*(j-1))%mod;
        }
    }
    cout << dp[n][1];
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 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 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 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 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 1108 KB Output is correct
13 Correct 1 ms 1068 KB Output is correct
14 Correct 1 ms 1108 KB Output is correct
15 Correct 1 ms 1108 KB Output is correct
16 Correct 1 ms 1108 KB Output is correct
17 Correct 1 ms 1108 KB Output is correct
18 Correct 1 ms 1108 KB Output is correct
19 Correct 1 ms 1108 KB Output is correct
20 Correct 1 ms 1108 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 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 468 KB Output is correct
10 Correct 1 ms 468 KB Output is correct
11 Correct 1 ms 468 KB Output is correct
12 Correct 1 ms 1108 KB Output is correct
13 Correct 1 ms 1068 KB Output is correct
14 Correct 1 ms 1108 KB Output is correct
15 Correct 1 ms 1108 KB Output is correct
16 Correct 1 ms 1108 KB Output is correct
17 Correct 1 ms 1108 KB Output is correct
18 Correct 1 ms 1108 KB Output is correct
19 Correct 1 ms 1108 KB Output is correct
20 Correct 1 ms 1108 KB Output is correct
21 Correct 3 ms 3784 KB Output is correct
22 Correct 3 ms 4040 KB Output is correct
23 Correct 3 ms 4384 KB Output is correct
24 Correct 13 ms 14036 KB Output is correct
25 Correct 15 ms 14028 KB Output is correct
26 Correct 15 ms 14100 KB Output is correct
27 Correct 14 ms 14036 KB Output is correct
28 Correct 9 ms 10120 KB Output is correct