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2014百度之星資格賽——XOR SUM

#include<cstdio>
#include<cstdlib>
#include<iostream>
#define LL long long

using namespace std;

LL power[32];

typedef struct TrieNode
{
	struct TrieNode *next[2];
}TrieNode;

void Init(TrieNode **root)
{
	*root=NULL;
}

TrieNode *CreateNode()
{
	TrieNode *p;
	p=(TrieNode *)malloc(sizeof(TrieNode));
	if(!p)
	{
		printf("No enough memory!\n");
		exit(-1);
	}
	p->next[0]=NULL;
	p->next[1]=NULL;
	return p;
}

void InsertNode(TrieNode **root,LL data)
{
	int i,k;
	TrieNode *p=*root;
	if(p==NULL)
	{
		p=*root=CreateNode();
	}
	for(i=31;i>=0;i--)
	{
		if(data&power[i])
			k=1;
		else
			k=0;
		if(p->next[k]==NULL)
			p->next[k]=CreateNode();
		p=p->next[k];
	}
}

LL Search(TrieNode *root,LL data)
{
	LL ans=0;
	TrieNode *p=root;
	for(int i=31;i>=0;i--)
	{
		if(data&power[i])//the No.i bit is 1
		{
			if(p->next[0])//to get the max xor value the same bit should 
				p=p->next[0];             //          be 0 if it exists
			else// if not exist ,then have to choose 1
			{
				ans|=power[i];
				p=p->next[1];
			}
		}
		else//the No.i bit is 0,so we should choose 1 if it exits
		{
			if(p->next[1])
			{
				ans|=power[i];
				p=p->next[1];
			}
			else
				p=p->next[0];
		}
	}
	return ans;
}

int main(int argc,char *argv[])
{
	LL t,n,m;
	scanf("%I64d",&t);
	for(LL i=1;i<=t;i++)
	{
		TrieNode *root;
		power[0]=1;
		for(int j=1;j<=31;j++)
			power[j]=power[j-1]<<1;
		Init(&root);
		printf("Case #%I64d:\n",i);
		scanf("%I64d%I64d",&n,&m);
		while(n--)
		{
			LL data;
			scanf("%I64d",&data);
			InsertNode(&root,data);
		}
		while(m--)
		{
			LL s;
			scanf("%I64d",&s);
			printf("%I64d\n",Search(root,s));
		}
	}
	return 0;
}