Submission #524774

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Source Code Expand

#include<iostream>
#include<cstdio>
#include<vector>
#include<queue>

#include<map>
#include<set>
#include<string>
#include<algorithm>
#include<functional>
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define INF 1<<30
#define MP make_pair
#define mp make_pair
#define pb push_back
#define PB push_back
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define ll long long
#define ull unsigned long long
struct path{
	int p,c;
	path(){p=0,c=0;}
	path(int p_,int c_){p=p_;c=c_;}
};
vector<path> g[100010];
int xr[100010];

int n,x;
void dfs(int tar,int par, int xx){
	xr[tar]=xx;
	REP(i,g[tar].size()){
		if(g[tar][i].p==par) continue;
		dfs(g[tar][i].p,tar, xx^g[tar][i].c);
	}
	return;
}
int main(){
cin.tie(0);
ios::sync_with_stdio(false);
	cin>>n>>x;
	REP(i,n-1){
		int x,y,c;cin>>x>>y>>c;x--;y--;
		g[x].pb(path(y,c));g[y].pb(path(x,c));
	}
	dfs(0,-1,0);
	map<int,ll> pa;
	ll ans=0;
	REP(i,n){
		ans += pa[ x^xr[i] ];
		pa[xr[i]]++;
	}
	cout<<ans<<endl;

}

Submission Info

Judge Result