Submission #876767

#	Time	Username	Problem	Language	Result	Execution time	Memory
876767		Ivkosqn	Jail (JOI22_jail)	C++14	0 / 100	2 ms	3396 KiB

jail

#include <bits/stdc++.h>
#define endl '\n'

using namespace std;

const int maxn = 120010;
int n, m, s[maxn], f[maxn], used[maxn];
vector<int> v[maxn];

void read(){
    cin >> n;
    for(int i = 1;i <= n;i++)
        v[i].clear();
    for(int i = 1;i <= n - 1;i++){
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    cin >> m;
    for(int i = 1;i <= m;i++){
        cin >> s[i] >> f[i];
    }
}

void dfs(int ver){
    if(used[ver] > 1)
        return;
    used[ver] = -1;
    for(int nb : v[ver]){
        if(used[nb])
            continue;
        dfs(nb);
    }
}

void solve(){
    read();
    for(int i = 1;i <= m;i++){
        for(int j = 1;j <= m;j++){
            if(i == j)
                continue;
            for(int k = 1;k <= n;k++)
                used[k] = 0;
            for(int k = 1;k <= m;k++)
                used[s[k]]++;
            dfs(s[j]);
            int cnt = 0;
            if(used[f[j]] != -1)
                cnt++;
            for(int k = 1;k <= n;k++)
                used[k] = 0;
            for(int k = 1;k <= m;k++)
                used[s[k]]++;
            dfs(s[i]);
            if(used[f[i]] != -1)
                cnt++;
            else{
                for(int k = 1;k <= n;k++)
                    used[k] = 0;
                for(int k = 1;k <= m;k++)
                    used[s[k]]++;
                used[s[i]]--;
                used[f[i]]++;
                dfs(s[j]);
                if(used[f[j]] != -1)
                    cnt++;
            }
            if(cnt == 2){
                cout << "No\n";
                return;
            }
        }
    }
    cout << "Yes\n";
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int t;
    cin >> t;
    while(t--){
        solve();
    }
    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 16
• Subtask 4: 0 / 28
• Subtask 5: 0 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23