Submission #1117702

#	Time	Username	Problem	Language	Result	Execution time	Memory
1117702		vjudge1	Kangaroo (CEOI16_kangaroo)	C++14	6 / 100	2049 ms	336 KiB

kangaroo

#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#define pb push_back
#define F first
#define S second
#define ll long long
#define int ll
#define pii pair<int, int>
#define io ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define M_PI 3.14159265358979323846
#define all(v) v.begin(), v.end()
#define pss pair<string, string>
#define no cout<<"No"<<endl;
#define yes cout<<"Yes"<<endl;
#define imp cout<<-1<<endl;
#define flu cout.flush();
#define Endl endl

const int N = 100009;
const int mod = 1e9+7;

int cnt=0, n, start, finish, used[2005];

void f(int now, int mo, int di){
    used[now]=1;
    if(mo==0){
        if(now==finish){
            cnt++;
            cnt=cnt%mod;
        }
        used[now]=0;
        return;
    }
    mo--;
    if(di==1){
        int q=now+1;
        while(q<=n){
            if(used[q]==0) f(q, mo, di*-1);
            q++;
        }
    }
    else{
        int q=now-1;
        while(q>=1){
            if(used[q]==0) f(q, mo, di*-1);
            q--;
        }
    }
    used[now]=0;
}

void solve(){
    cin>>n>>start>>finish;
    used[start]=1;
    f(start, n-1, 1);
    f(start, n-1, -1);
    cout<<cnt%mod<<endl;
}

signed main(){
    io;
    int t=1;
    //cin>>t;
    while(t--){
        solve();
    }
}

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