BZOJ 1603 [Usaco2008 Oct]打谷机 dfs

题意:链接

方法:暴力

解析:

搜1到n路径上的边权异或和….

这几个水题刷的我有点…..

代码:

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define N 1010using namespace std;int n,cnt;struct node{    int from,to,val,next;}edge[N<<1];int head[N];void init(){    memset(head,-1,sizeof(head));    cnt=1;}void edgeadd(int from,int to,int val){    edge[cnt].from=from,edge[cnt].to=to,edge[cnt].val=val;    edge[cnt].next=head[from];    head[from]=cnt++;}void dfs(int now,int fa,int worth){    if(now==n)    {        printf("%d\n",worth);        exit(0);    }    for(int i=head[now];i!=-1;i=edge[i].next)    {        int to=edge[i].to;        if(to==fa)continue;        dfs(to,now,worth^edge[i].val);    }}int main(){    init();    scanf("%d",&n);    for(int i=1;i<n;i++)    {        int x,y,z;        scanf("%d%d%d",&x,&y,&z);        edgeadd(x,y,z),edgeadd(y,x,z);    }    dfs(1,0,0);}