Submission #581618

#	Time	Username	Problem	Language	Result	Execution time	Memory
581618		Lobo	Jail (JOI22_jail)	C++17	72 / 100	4128 ms	1048576 KiB

jail

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

const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

const int maxn = 2e5+10;

int n, m, pp[maxn][25], pai[maxn], gr[maxn], h[maxn], s[maxn], t[maxn], st[maxn], ed[maxn];
vector<int> g[maxn], gts[maxn];

void dfslca(int u, int ant) {
    pai[u] = ant;
    pp[u][0] = ant;
    for(int i = 1; i <= 20; i++) {
        pp[u][i] = pp[pp[u][i-1]][i-1];
    }
    for(auto v : g[u]) if(v != ant) {
        h[v] = h[u]+1;
        dfslca(v,u);
    }
}

int lca(int u, int v) {
    if(h[u] < h[v]) swap(u,v);

    for(int i = 20; i >= 0; i--) {
        if(h[pp[u][i]] >= h[v]) {
            u = pp[u][i];
        }
    }
    if(u == v) return u;

    for(int i = 20; i >= 0; i--) {
        if(pp[u][i] != pp[v][i]) {
            u = pp[u][i];
            v = pp[v][i];
        }
    }
    return pp[u][0];
}

void solve() {
    cin >> n;
    for(int i = 1; i <= n; i++) {
        gr[i] = 0;
        g[i].clear();
        gts[i].clear();
        st[i] = 0;
        ed[i] = 0;
    }
    for(int i = 0; i < n-1; i++) {
        int u,v; cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }
    dfslca(1,1);
    cin >> m;
    for(int i = 1; i <= m; i++) {
        cin >> s[i] >> t[i];
        st[s[i]] = i;
        ed[t[i]] = i;
    }
    for(int i = 1; i <= m; i++) {
        int lc = lca(s[i],t[i]);
        // cout << s[i] << " "<< t[i] << " " << lc << endl;
        int v;
        v = s[i];
        while(true) {
            if(st[v] != 0 && v != s[i]) {
                gts[st[v]].pb(i);
                gr[i]++;
            }
            if(ed[v] != 0 && v != t[i]) {
                gts[i].pb(ed[v]);
                gr[ed[v]]++;
            }
            if(v == lc) break;
            v = pai[v];
        }
        v = t[i];
        while(true) {
            if(st[v] != 0 && v != s[i]) {
                gts[st[v]].pb(i);
                gr[i]++;
            }
            if(ed[v] != 0 && v != t[i]) {
                gts[i].pb(ed[v]);
                gr[ed[v]]++;
            }
            if(v == lc) break;
            v = pai[v];
        }
    }

    queue<int> q;
    for(int i = 1; i <= m; i++) {
        if(gr[i] == 0) q.push(i);
    }

    while(q.size()) {
        int u = q.front();
        q.pop();
        for(auto v : gts[u]) {
            if(--gr[v] == 0) q.push(v);
        }
    }

    string ans = "Yes";
    for(int i = 1; i <= m; i++) {
        if(gr[i] != 0) ans = "No";
    }
    cout << ans << endl;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    cin >> tt;
    while(tt--) {
        solve();
    }

}

• 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