Submission #1295752

#	Time	Username	Problem	Language	Result	Execution time	Memory
1295752		beater2k7	Kangaroo (CEOI16_kangaroo)	C++20	0 / 100	17 ms	23272 KiB

kangaroo

#include<bits/stdc++.h>
#define ll long long
#define pii pair<ll,ll>
using namespace std;
ll dp[2005][2005];
const ll MOD=1e9+7;
int main()
{
    freopen("kangaroo.in", "r", stdin);
    freopen("kangaroo.out", "w", stdout);
    int n,cs,cf;cin>>n>>cs>>cf;
    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];
                dp[i][j]%=MOD;
            }
            else{
                dp[i][j]=(dp[i-1][j+1]*j)%MOD+(dp[i-1][j-1]*(j-i>cs -i>cf))%MOD;
                dp[i][j]%=MOD;
            }
        }
    } 
    cout<<dp[n][1];
    return 0;   
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:9:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |     freopen("kangaroo.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:10:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     freopen("kangaroo.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49