Submission #7983090

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define all(x) (x).begin(),(x).end()
const int mod=1000000007,MAX=200001,INF=1<<30;

vector<pair<int,int>> G[MAX];
int P[MAX];

void DFS(int v,int p,int x){
    P[v]=x;
    for(pair<int,int> to:G[v]){
        if(to.first==p) continue;
        DFS(to.first,v,(x^to.second));
    }
}

int main(){
    
    int N,X;cin>>N>>X;
    for(int i=0;i<N-1;i++){
        int a,b,c;cin>>a>>b>>c;
        a--;b--;
        G[a].push_back({b,c});
        G[b].push_back({a,c});
    }
    DFS(0,-1,0);
    
    map<int,int> MA;
    
    for(int i=0;i<N;i++){
        MA[P[i]]++;
    }
    
    ll ans=0;
    
    for(int i=0;i<N;i++){
        if(X==0){
            ans+=MA[P[i]]-1;
        }else{
            ans+=MA[(P[i]^X)];
        }
    }
    
    cout<<ans/2<<endl;
}

Submission Info

Judge Result