1694D - Fake Plastic Trees - CodeForces Solution

#include <bits/stdc++.h>
#define ll long long int
#define pb push_back
#define ff first
#define ss second
#define rapid ios_base:: sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define ld long double
#define tc ll test; cin>>test; while(test--)
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>

const int N=2e5+10;
vector<ll> adj[N];
vector<pair<ll,ll>> vpp(N);
ll n;
ll ans;
ll DFS(ll v){
    ll sum =0;
    for(ll u:adj[v]){
        sum+= DFS(u);
    }

    if(sum< (vpp[v].first)){
        ++ans;
        return vpp[v].second;
    }

    return min(vpp[v].second,sum);
}

void solve(){
    cin>>n;

    ll par;
    for(ll i =2;i<=n;i++){
        cin>>par;
        adj[par].pb(i);
    }
    for(ll i=1;i<=n;i++){
        cin>>vpp[i].first>>vpp[i].second;
    }
    ans =0;
    DFS(1);
    cout<<ans<<endl;

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

}


int main() {
	// your code goes here
    // rapid;
    ll test;
	cin>>test;


	for(ll i =0;i<test;i++){
		solve();
	}
    
    	    
	return 0;
}