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Submission #316932

# Submission time Handle Problem Language Result Execution time Memory
316932 2020-10-28T15:52:32 Z Kuuhaku Kangaroo (CEOI16_kangaroo) C++17
100 / 100
 91 ms 14200 KB 
#define tasknames "Kangaroo"
#include <iostream>
#include <stdio.h>
using namespace std;
const int maxn=2e3+2;
int n, cs, cf, dp[maxn][maxn], mod=1e9+7;

void Enter()
{
    cin>>n>>cs>>cf;
    if(cs>cf)swap(cs,cf);
    dp[1][0]=1;
    for(int i=1;i<=n;i++)
        for(int j=0;j<=i;j++)
        {
            if(i==cs||i==cf)
            {
                dp[i+1][j]=(dp[i+1][j]+dp[i][j])%mod;
                if(j)dp[i+1][j-1]=(dp[i+1][j-1]+1ll*j*dp[i][j]%mod)%mod;
            }
            else
            {
                if(i>cf)
                    dp[i+1][j-1]=(dp[i+1][j-1]+1ll*j*dp[i][j]%mod)%mod;
                if(i>cs)
                    dp[i+1][j-1]=(dp[i+1][j-1]+1ll*j*dp[i][j]%mod)%mod;
                dp[i+1][j+1]=(dp[i+1][j+1]+dp[i][j])%mod;
                dp[i+1][j-1]=(dp[i+1][j-1]+1ll*j*(j-1)*dp[i][j]%mod)%mod;
            }
        }
    cout<<dp[n][0];
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if(fopen(tasknames".INP","r"))
    {
    	freopen(tasknames".INP","r",stdin);
        freopen(tasknames".OUT","w",stdout);
    }
    Enter();
}

Compilation message

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:40:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   40 |      freopen(tasknames".INP","r",stdin);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   41 |         freopen(tasknames".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 2 ms 1280 KB Output is correct
13 Correct 2 ms 1152 KB Output is correct
14 Correct 2 ms 1280 KB Output is correct
15 Correct 2 ms 1280 KB Output is correct
16 Correct 2 ms 1280 KB Output is correct
17 Correct 2 ms 1280 KB Output is correct
18 Correct 2 ms 1152 KB Output is correct
19 Correct 2 ms 1152 KB Output is correct
20 Correct 2 ms 1280 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 512 KB Output is correct
5 Correct 1 ms 512 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 512 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 2 ms 1280 KB Output is correct
13 Correct 2 ms 1152 KB Output is correct
14 Correct 2 ms 1280 KB Output is correct
15 Correct 2 ms 1280 KB Output is correct
16 Correct 2 ms 1280 KB Output is correct
17 Correct 2 ms 1280 KB Output is correct
18 Correct 2 ms 1152 KB Output is correct
19 Correct 2 ms 1152 KB Output is correct
20 Correct 2 ms 1280 KB Output is correct
21 Correct 11 ms 3840 KB Output is correct
22 Correct 12 ms 4096 KB Output is correct
23 Correct 14 ms 4480 KB Output is correct
24 Correct 79 ms 14200 KB Output is correct
25 Correct 82 ms 14200 KB Output is correct
26 Correct 81 ms 14200 KB Output is correct
27 Correct 91 ms 14072 KB Output is correct
28 Correct 54 ms 10264 KB Output is correct