제출 #848682

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
848682		danikoynov	Jail (JOI22_jail)	C++14	61 / 100	5033 ms	61944 KiB

jail

/**
 ____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|

**/

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 2e5 + 10;

int n, m, s[maxn], t[maxn];
vector < int > adj[maxn];
void input()
{
    cin >> n;
    for (int i = 1; i < n; i ++)
    {
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    cin >> m;
    for (int i = 1; i <= m; i ++)
    {
        cin >> s[i] >> t[i];
    }

}

int tin[maxn], tout[maxn], occ[2 * maxn], depth[maxn], timer;
void dfs(int v = 1, int p = -1)
{
    tin[v] = ++ timer;
    occ[timer] = v;
    for (int u : adj[v])
    {
        if (u == p)
            continue;

        depth[u] = depth[v] + 1;
        dfs(u, v);
        occ[++ timer] = v;
    }
    tout[v] = timer;
}

const int maxlog = 20;
int dp[maxlog][maxn * 2], lg[2 * maxn];

void build_sparse_table()
{
    for (int i = 1; i <= timer; i ++)
    {
        dp[0][i] = occ[i];
        lg[i] = lg[i / 2] + 1;
    }

    for (int j = 1; j < lg[timer]; j ++)
    {
        for (int i = 1; i <= timer - (1 << j) + 1; i ++)
        {
            dp[j][i] = dp[j - 1][i + (1 << (j - 1))];
            if (depth[dp[j - 1][i]] < depth[dp[j][i]])
                dp[j][i] = dp[j - 1][i];
        }
    }
}

int get_lca(int v, int u)
{
    int l = tin[v], r = tin[u];
    if (l > r)
        swap(l, r);
    int len = lg[r - l + 1] - 1;
    int lca = dp[len][r - (1 << len) + 1];
    if (depth[dp[len][l]] < depth[lca])
        lca = dp[len][l];
    return lca;
}

vector < int > graph[maxn];
bool is_cycle;

bool in_subtree(int v, int u)
{
    return (tin[v] <= tin[u] && tout[v] >= tout[u]);
}

bool on_path(int v, int u, int w)
{

    int lca = get_lca(v, u);
    if (in_subtree(lca, w) && in_subtree(w, v))
        return true;
    if (in_subtree(lca, w) && in_subtree(w, u))
        return true;
    return false;
}

void check_prisoners(int i, int j)
{
    if (on_path(s[i], t[i], s[j]) && on_path(s[i], t[i], t[j]))
    {
        is_cycle = true;
        return;
    }

    if (on_path(s[i], t[i], s[j]))
    {
        graph[i].push_back(j);
        return;
    }

    if (on_path(s[i], t[i], t[j]))
    {
        graph[j].push_back(i);
        return;
    }
}

void build_graph()
{
    for (int i = 1; i <= m; i ++)
    {
        for (int j = 1; j <= m; j ++)
        {
            if (i != j)
                check_prisoners(i, j);
        }
    }
}

int used[maxn];

void check_dag(int v)
{
    used[v] = 1;
    for (int u : graph[v])
    {
        if (used[u] == 2)
            continue;
            ///cout << v << " : " << u << endl;
        if (used[u] == 1)
            is_cycle = 1;
        else
        {
            check_dag(u);
        }
    }
    used[v] = 2;
}

void check_graph()
{
    for (int i = 1; i <= m; i ++)
    {
        if (!used[i])
            check_dag(i);
    }

    if (is_cycle)
        cout << "No" << endl;
    else
        cout << "Yes" << endl;
}

void clear_data()
{
    is_cycle = false;
    for (int i = 1; i <= m; i ++)
        graph[i].clear(), used[i] = 0;

    for (int i = 1; i <= n; i ++)
    {
        adj[i].clear();
    }
    timer = 0;
}

void solve()
{
    input();
    dfs();
    build_sparse_table();
    build_graph();
    check_graph();
    clear_data();

}

int main()
{
    speed();
    int q;
    cin >> q;
    while(q --)
        solve();
    return 0;
}

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