Submission #1104620

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104620		_callmelucian	Jail (JOI22_jail)	C++14	49 / 100	1048 ms	44552 KiB

jail

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

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;

#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())

const int mn = 1e5 + 5;
int up[mn][18], depth[mn], vis[mn];
vector<int> adj[mn], graph[mn];

void dfs (int u, int p, int d) {
    up[u][0] = p, depth[u] = d;
    for (int i = 1; i < 18; i++)
        up[u][i] = up[up[u][i - 1]][i - 1];
    for (int v : adj[u])
        if (v != p) dfs(v, u, d + 1);
}

int goUp (int a, int k) {
    for (int i = 0; i < 18; i++)
        if (k & (1 << i)) a = up[a][i];
    return a;
}

int lca (int a, int b) {
    if (depth[a] < depth[b]) swap(a, b);
    a = goUp(a, depth[a] - depth[b]);
    if (a == b) return a;
    for (int i = 17; i >= 0; i--)
        if (up[a][i] != up[b][i]) a = up[a][i], b = up[b][i];
    return up[a][0];
}

int distance (int a, int b) {
    return depth[a] + depth[b] - 2 * depth[lca(a, b)];
}

bool inPath (int node, int a, int b) {
    return distance(a, node) + distance(node, b) == distance(a, b);
}

bool detectCycle (int u) {
    if (vis[u] == 1) return 1;
    if (vis[u] == 2) return 0;
    vis[u] = 1;
    for (int v : graph[u])
        if (detectCycle(v)) return vis[u] = 2, 1;
    vis[u] = 2;
    return 0;
}

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

    int m; cin >> m;
    for (int i = 0; i < m; i++) {
        graph[i].clear();
        vis[i] = 0;
    }

    vector<pii> paths(m);
    for (int i = 0; i < m; i++)
        cin >> paths[i].first >> paths[i].second;

    for (int i = 0; i < m; i++) {
        vis[i] = 0;
        for (int j = 0; j < m; j++) {
            if (i == j) continue;
            if (inPath(paths[j].first, paths[i].first, paths[i].second) ||
                inPath(paths[i].second, paths[j].first, paths[j].second)) graph[j].push_back(i);
        }
    }
    for (int i = 0; i < m; i++)
        if (!vis[i] && detectCycle(i)) return cout << "No\n", void();

    cout << "Yes\n";
}

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

    int TC; cin >> TC;
    while (TC--) solve();

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 28 / 28
• Subtask 5: 0 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23