hdu 4665 搜索

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#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cstring>

using namespace std;

int belong[5010],num[5010],n;

int dfs(int s,int pre,int cur)

{

    int i,j;

    if(cur==n/2)

        return 1;

    for(i=s;i<=n;i++)

    {

        if(belong[i]==-1)

        {

            belong[i]=0;

            for(j=i+1;j<=n;j++)

            if(belong[j]==-1&&num[i]==num[j]&&j>pre)

            {

                belong[j]=1;

                if(dfs(s+1,j,cur+1))

                    return 1;

                belong[j]=-1;

            }

            belong[i]=-1;

            break;

        }

    }

    return 0;

}

int main()

{

    int t,i,j;

    scanf("%d",&t);

    while(t--)

    {

        memset(belong,-1,sizeof(belong));

        scanf("%d",&n);

        for(i=1;i<=n;i++)

            scanf("%d",num+i);

        dfs(1,0,0);

        for(i=1;i<=n;i++)

            printf("%d",belong[i]);

        printf("\n");

    }

    return 0;

}