Hanuman and Tree (Programming Contest #1 (Chapter 'Ramayan') )

help
1

https://www.codechef.com/PCR12020/problems/HTREE
It is clarified in announcement that node 1 is always the root of tree.

#include<bits/stdc++.h>
#include<algorithm>
#include<vector>
#include<queue>
#include<set>
#include<stack>
#include<numeric>
using namespace std;

#define ll long long
#define endl "\n"
#define pb push_back
#define mp make_pair

map<ll,ll> tree;

void dfs(vector<ll> t[],ll node,vector<bool> visited)
{
    visited[node]=true;
    
    for(ll x:t[node])
    {
        if(!visited[x])
        {
            tree[x+1]=node+1;
            dfs(t,x,visited);
        }
    }
}

int solve()
{
    ll n,q,a,b;
    cin>>n>>q;

    vector<ll> t[n];
    
    for(ll i=0;i<n-1;i++)
    {
        cin>>a>>b;
        t[a-1].pb(b-1);
        t[b-1].pb(a-1);
    }
    
    vector<bool> visited(n,false);
    
    dfs(t,0,visited);
    
    for(ll i=0;i<q;i++)
    {
        cin>>a>>b;
        
        ll ans=0;
        
        while(b--)
        {
            ans=tree[a];
            
            if(ans==0)
                break;
                
            a=tree[a];
        }
        
        if(ans==0)
            cout<<-1<<endl;
        else
            cout<<ans<<endl;
    }
    

    return 0;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    /*ll t;
    cin>>t;
    while(t--)*/
        solve();

    return 0;
}

I am not understanding where I went wrong.

2

Your code takes O(b) time to process the queries, which is way too slow.

3

@everule1 Yes I got it. Thankyou.