Company Queries II

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

typedef long long ll;

const ll N = 200000;

vector<ll> adj[N];
bool visited[N];

void dfs(ll s, ll array[], ll depth) {
    if (visited[s]) return;
    visited[s] = true;
    
    array[s] = depth;

    for (auto u: adj[s]) {
        dfs(u, array, depth+1);
    }
}

int main() {
    ll n,q;
    cin >> n >> q;

    ll a,b;
    ll ancestors[n+1];
    for(ll i = 0; i<n-1; i++) {
        cin >> a;
        ancestors[i+2] = a;
        adj[a].push_back(i+2);
    }

    ll array[n+1];

    dfs(1,array,1);

    // for(ll i = 0; i<n; i++) {
    //     cout << i+1 << " " << array[i+1] << endl;
    // }

    ll outputs[q];
    ll ances_pairs[n+1][n+1] = {0};
    for(ll i = 0; i<q; i++) {
        cin >> a >> b;
        if(array[a] < array[b]) swap(a,b);
        while(array[a] != array[b]) {
            a = ancestors[a];
        }

        ll p_a = a;
        ll p_b = b;
        while(a != b) {
            if(ances_pairs[a][b] != 0) {
                b = ances_pairs[a][b];
                break;
            }
            a = ancestors[a];
            b = ancestors[b];
        }
        outputs[i] = b;
        ances_pairs[p_a][p_b] = b;
        
    }

    for(ll i = 0; i<q; i++) {
        cout << outputs[i] << endl;
    }

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: RUNTIME ERROR

Test 7

Verdict: RUNTIME ERROR

Test 8

Verdict: RUNTIME ERROR

Test 9

Verdict: RUNTIME ERROR

Test 10

Verdict: RUNTIME ERROR

Test 11

Verdict: ACCEPTED

Test 12

Verdict: RUNTIME ERROR