acdream 1726 A Math game

/* ***********************************************Author        :xryzEmail         :[e-mail] Time  :7-11 11:59:34File Name     :2015_07_11.cpp************************************************ */#include <stdio.h>#include <string.h>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <set>#include <map>#include <string>#include <math.h>#include <stdlib.h>#include <time.h>using namespace std;int a[50],h,n,use[50],sum[50],flag;void dfs(int x,int cnt){    if(cnt==h)    {        flag=1;        return ;    }    if(cnt+sum[x]<h||cnt>h) return ;    if(use[x]==0)    {        use[x]=1;        dfs(x-1,cnt+a[x]);        use[x]=0;    }    dfs(x-1,cnt);    return ;}int main(){    int  i;    while(~scanf("%d%d",&n,&h))    {        memset(a,0,sizeof(a));        memset(sum,0,sizeof(sum));        sum[0]=0;        for(i=1; i<=n; i++)        {            scanf("%d",&a[i]);            sum[i]=sum[i-1]+a[i];        }        memset(use,0,sizeof(use));        flag=0;        dfs(n,0);        if(flag==1)            printf("Yes\n");        else            printf("No\n");    }    return 0;}