Submission #955765

#	Time	Username	Problem	Language	Result	Execution time	Memory
955765		aymanrs	Jail (JOI22_jail)	C++14	77 / 100	3250 ms	1048576 KiB

jail

#include<bits/stdc++.h>
using namespace std;
bool f; int T;
void dfs(int n, vector<int> g[], int p, int d[], int pa[]){
    pa[n] = p;
    d[n] = d[p]+1;
    for(int c : g[n]){
        if(c == p) continue;
        dfs(c, g, n, d, pa);
    }
}
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(){
    bool s1 = true;
    int n,m;cin >> n;
    vector<int> g[n+1];
    for(int i = 1;i < n;i++){
        int u, v;cin >> u >> v;
        s1 &= (u == i) && (v == i+1);
        g[u].push_back(v);
        g[v].push_back(u);
    }
    if(s1){
        cin >> m;
        set<int> fore, bace;
        pair<int, int> ra[m];
        bool ok = true;
        for(int i = 0;i < m;i++){
            cin >> ra[i].first >> ra[i].second;
            if(ra[i].first < ra[i].second) {
                fore.insert(ra[i].second);
                fore.insert(ra[i].first);
                auto p = bace.lower_bound(ra[i].first);
                if(p != bace.end() && *p <= ra[i].second) ok = false;
            }
            else {
                bace.insert(ra[i].second);
                bace.insert(ra[i].first);
                swap(ra[i].first, ra[i].second);
                auto p = fore.lower_bound(ra[i].first);
                if(p != fore.end() && *p <= ra[i].second) ok = false;
            }
        }
        if(!ok){
            cout << "No\n";
            return;
        }
        sort(ra, ra+m, [](const auto& a, const auto& b){
            if(a.first != b.first) return a.first < b.first;
            return a.second > b.second;
        });
        int R = -1;
        for(auto p : ra){
            if(R >= p.second){
                cout << "No\n";
                return;
            }
            R = max(R, p.second);
        }
        cout << "Yes\n";
        return;
    }
    int d[n+1], p[n+1];d[0] = 0;
    dfs(1, g, 0, d, p);
    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;
        if(d[s[i]] < d[t[i]]) swap(s[i], t[i]);
        while(d[s[i]] > d[t[i]]){
            path.push_back(s[i]);
            s[i] = p[s[i]];
        }
        while(true){
            path.push_back(s[i]);
            if(s[i] == t[i]) break;
            path.push_back(t[i]);
            s[i] = p[s[i]];t[i] = p[t[i]];
        }
        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: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 28 / 28
• Subtask 5: 12 / 12
• Subtask 6: 11 / 11
• Subtask 7: 0 / 23