不正经题解|隐藏元素

非常简单，有脚就行

#include <iostream>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>
#pragma GCC optimize(3,"Ofast","inline")
#pragma GCC optimize(2,"Ofast","inline")
#pragma GCC optimize(1,"Ofast","inline")
using namespace std;
const int N=2e5+5;
int n,m,h[N],e[N],ne[N],w[N],a[N],idx;
void add(int x,int y,int k) {
	e[idx]=y,w[idx]=k,ne[idx]=h[x],h[x]=idx++;
}
map<int,bool> vis;
void A(int x) {
	int len=0;
	vector<int> ve;
	for (int i=h[x];i!=-1;i=ne[i]) {
		int j=e[i],k=w[i];
		if (vis[j]==0) {
			a[j]=a[x]^k;
			ve.push_back(j);
			len++;
			vis[j]=1;
		}
	}
	for (int i=0;i<len;i++) {
		A(ve[i]);
	}
}
int main() {
	memset(h,-1,sizeof h);
	memset(a,0x7f,sizeof a);
	scanf("%d %d",&n,&m);
	a[1]=1;
	for (int i=1,c=1;i<=m;i++) {
		int x,y,k;
		scanf("%d %d %d",&x,&y,&k);
		add(x,y,k);
		add(y,x,k);
		if (a[x]!=0x7f7f7f7f) {
			A(x);
		} 
		if (a[y]!=0x7f7f7f7f) {
			A(y);
		}
	}
	for (int i=1;i<=n;i++) {
		if (a[i]==0x7f7f7f7f) {
			printf("-1 ");
		}else printf("%d ",a[i]);
	}
	return 0;
}