Submission #994213

#	Time	Username	Problem	Language	Result	Execution time	Memory
994213		vjudge1	Jail (JOI22_jail)	C++17	72 / 100	5116 ms	981288 KiB

jail

#include <bits/stdc++.h>
    
using namespace std;
using ll = long long;
    
const int MAXN = 120'001;
    
vector<int> g[MAXN], g2[MAXN];
int tin[MAXN], tout[MAXN], s[MAXN], e[MAXN], par[MAXN], col[MAXN], hv[MAXN], timer;
bool ok;
    
void dfs(int u, int p = -1) {
    tin[u] = timer++;
    par[u] = p;
    for (int v : g[u]) {
        if (v != p) dfs(v, u);
    }
    tout[u] = timer++;
}
    
void dfs2(int u) {
    col[u] = 1;
    for (int v : g2[u]) {
        if (col[v] == 0) dfs2(v);
        else if (col[v] == 1) ok = false;
    }
    col[u] = 2;
}
    
bool is_ancestor(int u, int v) {
    return tin[u] <= tin[v] && tout[v] <= tout[u];
}
    
void solve() {
    int n; cin >> n;
    ok = true;
    fill(s, s+n+1, 0);
    fill(e, e+n+1, 0);
    fill(col, col+n+1, 0);
    fill(hv, hv+n+1, 0);
    timer = 1;
    for (int i = 1; i <= n; i++) {
        g[i].clear();
        g2[i].clear();
    }
    for (int i = 0; i < n-1; i++) {
        int u, v; cin >> u >> v;
        g[u].emplace_back(v);
        g[v].emplace_back(u);
    }
    dfs(1);
    int m; cin >> m;
    vector<pair<int, int>> edges(m+1);
    for (int i = 1; i <= m; i++) {
        cin >> edges[i].first >> edges[i].second;
        auto [u, v] = edges[i];
        s[u] = e[v] = i;
        hv[edges[i].first] = i;
    }
    auto calc = [&](int u, int v, vector<int> &indices, bool add_lca) {
        while (!is_ancestor(u, v)) {
            indices.emplace_back(u);
            u = par[u];
        }
        if (add_lca) indices.emplace_back(u);
    };
    vector<int> cnt(m+1, 0);
    for (int i = 1; i <= m; i++) {
        vector<int> indices;
        {
            auto [u, v] = edges[i];
            calc(u, v, indices, false);
            calc(v, u, indices, true);
        }
        
        vector<int> to_rem;
        for (int u : indices) {
            if (e[u] && e[u] != i) {
                to_rem.emplace_back(e[u]);
                cnt[e[u]]++;
                g2[i].emplace_back(e[u]);
            }
            if (s[u] && s[u] != i) {
                to_rem.emplace_back(s[u]);
                cnt[s[u]]++;
                g2[s[u]].emplace_back(i);
            }
        }
        for (int i : to_rem) {
            if (cnt[i] == 2) ok = false;
            else cnt[i] = 0;
        }
    }

    for (int i = 1; i <= m; i++) {
        if (col[i] == 0) dfs2(i);
    }
    cout << (ok?"Yes\n":"No\n");
}
    
int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int t; cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

• Subtask 1: 0 / 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