KOI: Tree

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

const int N = 2e5 + 10;

vector<int> adj[N];
int pr[N], color[N];

void DFS(int u, int p, int prv, int cur){
    color[u] = cur;
    for(int v : adj[u]){
        if(v == p){
            continue;
        }
        if(color[v] == prv){
            DFS(v, u, prv, cur);
        }
    }
}

int main(){

    int nVertex, Q;
    scanf("%d%d", &nVertex, &Q);
    pr[1] = 0;
    int colorCnt = 0;
    color[1] = ++colorCnt;
    for(int u = 2; u <= nVertex; ++u){
        scanf("%d", &pr[u]);
        adj[u].push_back(pr[u]);
        adj[pr[u]].push_back(u);
        color[u] = colorCnt;
    }
    while(Q--){
        int u, v, cmd;
        scanf("%d%d%d", &u, &v, &cmd);
        int cut = 0;
        if(color[u] == color[v]){
            cout << "YES\n";
            cut = u;
        } else {
            cout << "NO\n";
            cut = v;
        }
        if(cmd == 0 || color[cut] != color[pr[cut]]){
            continue;
        }
        DFS(cut, pr[cut], color[cut], ++colorCnt);
    }

    return 0;
}
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