Submission #1502042

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Source Code Expand

#include<iostream>
#include<algorithm>
#include<vector>
#include<cstdio>
#include<list>
#include<queue>
#include<string.h>
#include<functional>
#include<stack>
#include<deque>
#include<string>
#include<limits.h>
#include<map>
#include<set>
#include<unordered_map>
#include<cmath>
#include<unordered_set>
#define int long long
#define P pair<int,int>//to bit
using namespace std;

unordered_map<int, int>u;
vector<P>r[100000];
void DFS(int n, int p, int x) {
	u[x]++;
	for (P b : r[n]) {
		if (b.first != p) {
			DFS(b.first, n, x^b.second);
		}
	}
}
signed main() {
	int n, x; cin >> n >> x;
	for (int i = 1; i < n; i++) {
		int a, b, c; cin >> a >> b >> c; a--; b--;
		r[a].push_back({ b,c });
		r[b].push_back({ a,c });
	}
	DFS(0, 0, 0);
	int ans = 0;
	for (auto i : u) {
		if (x) {
			ans += i.second*u[i.first^x];
			if (u[i.first^x]==0) {
				u.erase(i.first^x);
			}
		}
		else {
			ans += i.second*(i.second - 1);
		}
	}
	cout << ans/2 << endl;
}

Submission Info

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