Submission #955741

#	Time	Username	Problem	Language	Result	Execution time	Memory
955741		aymanrs	Jail (JOI22_jail)	C++14	61 / 100	5025 ms	31688 KiB

jail

#include<bits/stdc++.h>
using namespace std;
bool f; int T;
void dfs(int n, vector<int> g[], int p, vector<int>& path){
    path.push_back(n);
    if(n == T){
        f = true;
        return;
    }
    for(int c : g[n]){
        if(f) break;
        if(c == p) continue;
        dfs(c, g, n, path);
    }
    if(!f) path.pop_back();
}
struct node {
    vector<node*> l;
    bool v = false, c = false;
};
bool ans;
void dfs(node* n){
    n->v = n->c = true;
    for(node* c : n->l){
        if(!ans) break;
        if(c->c){
            ans = false;
            break;
        }
        if(!c->v) dfs(c);
    }
    n->c = false;
}
void solve(){
    int n,m;cin >> n;
    vector<int> g[n+1];
    for(int i = 1;i < n;i++){
        int u, v;cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    cin >> m;
    int s[m], t[m];
    int sn[n+1], tn[n+1];
    fill(sn+1, sn+n+1, -1);fill(tn+1, tn+n+1, -1);
    for(int i = 0;i < m;i++){
        cin >> s[i] >> t[i];
        sn[s[i]] = i;
        tn[t[i]] = i;
    }
    node mg[m];
    for(int i = 0;i < m;i++){
        vector<int> path;
        f = false;T = t[i];
        dfs(s[i], g, -1, path);
        for(int _ : path){
            if(sn[_] != -1 && sn[_] != i) mg[i].l.push_back(&mg[sn[_]]);
            if(tn[_] != -1 && tn[_] != i) mg[tn[_]].l.push_back(&mg[i]);
        }
    }
    ans = true;
    for(int i = 0;i < m && ans;i++){
        if(!mg[i].v) dfs(&mg[i]);
    }
    if(ans)cout << "Yes\n";
    else cout << "No\n";
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int t;cin >> t;
    while(t--) solve();
}

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