Submission #607347

#	Time	Username	Problem	Language	Result	Execution time	Memory
607347		A_D	Kangaroo (CEOI16_kangaroo)	C++14	0 / 100	0 ms	340 KiB

kangaroo

#include <bits/stdc++.h>
#define int long long
#define ii pair<int,int>
#define F first
#define S second
using namespace std;
const int MOD=1e9+7;
int dp[2123][2123];
void solve()
{
    int n,s,e;
    cin>>n>>s>>e;
    if(s!=1&&e!=1)dp[1][2]=1;
    else dp[1][1]=1;
    for(int i=2;i<=n;i++){
        for(int j=0;j<=n;j++){
            if(i==s||i==e){
                if(j>1){
                    dp[i][j]+=dp[i-1][j-1];
                    dp[i][j]%=MOD;
                }
                dp[i][j]+=dp[i-1][j+1];
                dp[i][j]%=MOD;
            }
            else{
                if(j>2){
                    dp[i][j]+=dp[i-1][j-2];
                    dp[i][j]%=MOD;
                }
                dp[i][j]+=dp[i-1][j+2];
                dp[i][j]%=MOD;
            }
//            cout<<dp[i][j]<<" ";
        }
   //     cout<<"\n";
    }
    cout<<dp[n][0]<<"\n";
}

main()
{
    /*
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
//    */
    int t=1;
//    cin>>t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

kangaroo.cpp:40:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   40 | main()
      | ^~~~

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