64 lines
1.1 KiB
C++
64 lines
1.1 KiB
C++
#include <iostream>
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#include <bits/stdc++.h>
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using namespace std;
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const int MAXN = 1e6;
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vector<int> tree[MAXN];
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int lel[MAXN];
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int in[MAXN];
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int out[MAXN];
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int timer = 0;
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bool is_anc(int a, int b) {
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return (in[a] <= in[b]) && (out[b] <= out[a]);
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}
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void dfs(int v, int p, int h) {
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lel[v] = h;
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in[v] = timer++;
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for (int u : tree[v]) {
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if (u == p) {
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continue;
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}
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dfs(u, v, h + 1);
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}
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out[v] = timer++;
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}
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int main() {
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//assert(freopen("../4/A.txt", "r", stdin));
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ios_base::sync_with_stdio(false);
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cin.tie(0);
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int n, m, k;
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cin >> n >> m >> k;
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for (int i = 1; i < n; i++) {
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int v;
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cin >> v;
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tree[i].push_back(--v);
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tree[v].push_back(i);
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}
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dfs(0, -1, 0);
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for (int i = 0; i < m; i++) {
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int vi, ui;
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cin >> vi >> ui;
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--vi;
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--ui;
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if (!is_anc(vi, ui)){
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cout << "no\n";
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continue;
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}
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if (lel[ui] - lel[vi] > k) {
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cout << "no\n";
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} else {
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cout << "yes\n";
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}
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}
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}
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