BZOJ-2115: [Wc2011] Xor

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/C_13579/article/details/82703370

地址：https://www.lydsy.com/JudgeOnline/problem.php?id=2115

思路：引用dalao的博客题解：https://www.cnblogs.com/ljh2000-jump/p/5869991.html

Code:

#include<iostream>
#include<vector>
#include<cstdio>
#include<cstring>
using namespace std;
typedef long long LL;

const int MAX_N=50005;
const int MAX_M=100005;
struct node{
    int to;
	int next;
	LL w;
}edge[MAX_M<<1];
int n,m;
int head[MAX_M],num,Maxd,id;
LL boo[MAX_N];
LL f[65];

inline void add_edge(int u,int v,LL w)
{
    edge[num].to=v;
    edge[num].next=head[u];
    edge[num].w=w;
    head[u]=num++;
}
void DFS(int S);
void Insert(LL x);
int main()
{
	memset(boo,-1,sizeof(boo));
	memset(head,-1,sizeof(head));
	scanf("%d%d",&n,&m);
	int u,v;
	LL w;
	for(int i=0;i<m;++i)
	{
		scanf("%d%d%lld",&u,&v,&w);
		add_edge(u,v,w);
		add_edge(v,u,w);
	}
	boo[1]=0;
	DFS(1);
	LL ans=boo[n];
	for(int i=63;i>=0;--i)
		if((ans^f[i])>ans)	ans^=f[i];
	printf("%lld\n",ans);
	
	return 0;
}

void DFS(int S)
{
	for(int i=head[S];i!=-1;i=edge[i].next)
    {
        int v=edge[i].to;
		LL w=edge[i].w;
        if(boo[v]==-1){
        	boo[v]=boo[S]^w;
        	DFS(v);
		}else	Insert(boo[v]^boo[S]^w);
    }
}

void Insert(LL x)
{
	for(int i=63;i>=0;--i)
		if(x>>i){
			if(!f[i]){
				f[i]=x;	break;
			}
			x^=f[i];
		}
}