Submission #1284414

#	Time	Username	Problem	Language	Result	Execution time	Memory
1284414		Icelast	Jail (JOI22_jail)	C++20	61 / 100	5092 ms	32864 KiB

jail

#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 5*1e5+5, INF = 4e18+9;
struct Tree{
    int n, root;
    vector<int> depth, head, sz, pa;
    vector<int> f;
    Tree(int n, int root, vector<vector<int>> &adj): n(n), root(root){
        depth.resize(n+1, -1);
        head.resize(n+1);
        sz.resize(n+1, 0);
        pa.resize(n+1, -1);
        auto rootTree = [&](auto rootTree, int u, int p) -> void{
            depth[u] = depth[p]+1;
            pa[u] = p;
            sz[u] = 1;
            for(int v : adj[u]){
                if(v == p) continue;
                rootTree(rootTree, v, u);
                sz[u] += sz[v];
            }
        };
        rootTree(rootTree, root, 0);
        auto decompose = [&](auto decompose, int u, int h) -> void{
            head[u] = h;
            int heavy = -1;
            for(int v : adj[u]){
                if(v == pa[u]) continue;
                if(heavy == -1 || sz[heavy] < sz[v]) heavy = v;
            }
            if(heavy != -1) decompose(decompose, heavy, h);
            for(int v : adj[u]){
                if(v == pa[u] || v == heavy) continue;
                decompose(decompose, v, v);
            }
        };
        decompose(decompose, root, root);
        f = [&]{
            vector<array<int, 2>> first(n+1);
            vector<array<int, 2>> second(n+1);
            function<void(int, int)> dfs0 = [&](int u, int p) {
                first[u] = second[u] = {0, -1};
                for (int v : adj[u]) {
                    if (v == p) {
                        continue;
                    }
                    dfs0(v, u);
                    auto fetch = first[v];
                    fetch[0] += 1;
                    fetch[1] = v;
                    if (fetch > first[u]) {
                        swap(fetch, first[u]);
                    }
                    if (fetch > second[u]) {
                        swap(fetch, second[u]);
                    }
                }
            };
            dfs0(1, 0);

            function<void(int, int)> dfs = [&](int u, int p) {
                for (int v : adj[u]) {
                    if (v == p) {
                        continue;
                    }
                    auto fetch = first[u][1] == v ? second[u] : first[u];
                    fetch[0] += 1;
                    fetch[1] = u;
                    if (fetch > first[v]) {
                        swap(fetch, first[v]);
                    }
                    if (fetch > second[v]) {
                        swap(fetch, second[v]);
                    }
                    dfs(v, u);
                }
            };
            dfs(1, 0);
            vector<int> f(n+1);
            for (int u = 1; u <= n; u++) {
                f[u] = first[u][0];
            }
            return f;
        }();
    };
    int lca(int u, int v){
        for(; head[u] != head[v]; v = pa[head[v]]){
            if(depth[head[u]] > depth[head[v]]) swap(u, v);
        }
        if(depth[u] > depth[v]) swap(u, v);
        return u;
    }
    int dist(int u, int v) {
        return depth[u]+depth[v]-2*depth[lca(u, v)];
    }
};
void solve(){
    int n;
    cin >> n;
    vector<vector<int>> adj(n+1);
    for(int i = 1; i < n; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    Tree Y(n, 1, adj);
    int m;
    cin >> m;
    vector<int> s(m+1), t(m+1);
    for(int i = 1; i <= m; i++){
        cin >> s[i] >> t[i];
    }
    vector<vector<int>> g(m+1);
    for(int i = 1; i <= m; i++){
        for(int j = 1; j <= m; j++){
            if(i == j) continue;
            if(Y.dist(s[i], s[j]) + Y.dist(s[j], t[i]) == Y.dist(s[i], t[i])){
                g[i].push_back(j);
            }
            if(Y.dist(s[i], t[j]) + Y.dist(t[j], t[i]) == Y.dist(s[i], t[i])){
                g[j].push_back(i);
            }
        }
    }
    vector<int> vis(m+1, 0);
    bool ok = true;
    auto dfs = [&](auto dfs, int u) -> void{
        vis[u] = 1;
        for(int v : g[u]){
            if(vis[v] == 1){
                ok = false;
                return;
            }
            if(vis[v] == 2){
                continue;
            }
            dfs(dfs, v);
        }
        vis[u] = 2;
    };
    for(int i = 1; i <= m; i++){
        if(vis[i] == 0){
            dfs(dfs, i);
        }
    }
    if(ok){
        cout << "Yes";
    }else{
        cout << "No";
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    while(t--){
        solve();
        cout << "\n";
    }
    return 0;
}

• 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