NYOJ927 The partial sum problem

搜索的入门，学会思想吧！

#include <iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;

int n,s[10009],i,sum,ssum;
bool dfs(int pos,int sum)
{
    if(sum==ssum)
        return 1;
    if(pos==n||(ssum>0&&s[pos]>ssum)||(sum>0&&sum>ssum))
        return 0;
    if(dfs(pos+1,sum+s[pos]))//判断是从第几位开始计算
        return 1;
    else
        return dfs(pos+1,sum);
    return 0;
}
int main()
{
    while(scanf("%d",&n)==1)
    {
        for(i=0;i<n;i++)
        {
            scanf("%d",&s[i]);
        }
        scanf("%d",&ssum);
        sort(s,s+n);
        if(dfs(0,0))
            printf("Of course,I can!\n");
        else
            printf("Sorry,I can't!\n");

    }
    return 0;
}