Submission #721111

#	Time	Username	Problem	Language	Result	Execution time	Memory
721111		saayan007	Jail (JOI22_jail)	C++17	0 / 100	10 ms	3520 KiB

jail

#include "bits/stdc++.h"
using namespace std;

#define int long long
#define fr first
#define sc second
#define eb emplace_back
#define nl "\n"

/* const int logn = 20; */
/* int anc[N][logn + 1], depth[N]; */

/* void dfs(int cur = 1, int par = 0) { */
/*     depth[cur] = depth[par] + 1; */
/*     anc[cur][0] = par; */
/*     for(auto u : adj[cur]) { */
/*         if(u == par) continue; */
/*         dfs(u, cur); */
/*     } */
/* } */

/* void precompute() { */
/*     dfs(); */
/*     for(int i = 1; i <= logn; ++i) { */
/*         for(int j = 1; j <= n; ++j) { */
/*             if(depth[j] <= (1LL << i)) */
/*                 anc[i][j] = 0; */
/*             else */
/*                 anc[i][j] = anc[anc[i][j - 1]][j - 1]; */
/*         } */
/*     } */
/* } */

/* int lca(int a, int b) { */
/*     if(a == b) return a; */
/*     if(depth[a] > depth[b]) swap(a, b); */
/*     for(int j = logn; j >= 0; --j) { */
/*         if(anc[b][j] != 0 && depth[anc[b][j]] >= depth[a]) */
/*             b = anc[b][j]; */
/*     } */

/*     if(a == b) return a; */
/*     for(int j = logn; j >= 0; --j) { */
/*         if(anc[a][j] != 0 && and[a][j] != anc[b][j]) { */
/*             a = anc[a][j]; */
/*             b = anc[b][j]; */
/*         } */
/*     } */
/*     return anc[a][0]; */
/* } */

/* void mod(int a, int b) { */
/*     int l = lca(a, b); */
/* } */

const int N = 120001;
int n, m;
vector<int> adj[N];
int s[N], t[N];
int from[N];
int use[N];

void dfs(int cur, int par) {
    from[cur] = par;
    for(auto u : adj[cur]) {
        if(u != par)
            dfs(u, cur);
    }
}

void mod(int a, int b, int v = 1) {
    dfs(a, 0);
    while(b != 0) {
        use[b] += v;
        b = from[b];
    }
}

void solve() {
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        use[i] = 0;
        adj[i].clear();
    }
    for(int i = 1; i < n; ++i) {
        int a, b; cin >> a >> b;
        adj[a].eb(b); adj[b].eb(a);
    }

    cin >> m;
    for(int i = 1; i <= m; ++i) {
        cin >> s[i] >> t[i];
    }

    for(int i = 1; i <= m; ++i) {
        mod(s[i], t[i]);
    }

    set<pair<int, int>> st;
    for(int i = 1; i <= m; ++i) {
        st.insert({use[t[i]], i});
    }
    while(!st.empty()) {
        int a = (*st.begin()).sc;
        if(use[t[a]] > 1) {
            cout << "No" << nl;
            return;
        }
        mod(s[a], t[a], -1);
        st.erase(st.begin());
    }
    cout << "Yes" << nl;
}

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int t = 1;
    cin >> t;
    for(int i = 1; i <= t; ++i) {
        /* cout << "Case #" << i << nl; */
        solve();
        /* cout << nl; */
    }
}

• 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