zju 1204 一直runtime error

[fdar]

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1204

测试数据对了，但是一直runtime error， 但是坚持了很久也没发现数组越界的地方，请问哪里错了...

#include <iostream>
#include <algorithm> 
using namespace std;

int used[32];								//放达成条件的数字
int dig[32];								//放数字
int t, n, len, last, flag;

int cmp( const void *p1, const void *p2) {
    return *((int *)p1) - *((int *)p2);
}

void dfs(int a, int k, int sum, int x) {						//回溯
        int i;
        if( len == a ) {
			if(binary_search(dig, dig + n, sum)) {
                  flag = 1;
                  for( i = 0; i < k; i++ ) {
                     if( i != k - 1)
                         printf("%d+", used[i]);
                     else
                         printf("%d=%d\n", used[i], sum);
                  }
            }
            return;
        }

        else {
			 
             for( i = x; i < n; i++ ) {        
                  if( sum + dig[i] > last ) return;
				  used[k] = dig[i];
                  sum += dig[i];
                  dfs(a+1, k+1, sum, i+1);
                  sum -= dig[i];
             }
             
        }

}

int main() {
    int i, j, sum, k;
    scanf("%d", &t);
    memset(used, 0, sizeof(used));
    while(t--) {
            scanf("%d", &n);
            for( i = 0; i < n; i++ )
                 scanf("%d", &dig[i]);
            qsort(dig, n, sizeof(dig[0]), cmp);
            k = 0; last = dig[n-1];
            flag = 0; 
            for( len = 2; len < n; len++) {
                 sum = 0;
                 for( i = 0; i < n; i++ ) {
                     used[k] = dig[i];
                     sum += dig[i];
                     dfs(1, k+1, sum, i+1);
                     sum -= dig[i];
                 }
            }
            if(!flag)
				printf("Can't find any equations.\n");
			if(t) printf("\n");
    }    
    system("pause");
    return 0;   
}

[baihacker]

//this code can ac the problem
//这是一个简单的搜索题目

#include <iostream>
#include <deque>
#include <vector>
using namespace std;

int n, data[35], found, sol[35];

int exist(int value)
{
	int lo = 0, hi = n - 1;
	while (lo<=hi)
	{
		int mid = (lo+hi)/2;
		if (data[mid] == value)return 1;
		if (value < data[mid]) hi = mid - 1;
		else lo = mid + 1;
	}
	return 0;
}

void search(int start, int dest_cnt, int curr_cnt, int curr_sum)
{
	if (curr_cnt == dest_cnt)
	{
		if (exist(curr_sum))
		{
			for (int i = 0; i < dest_cnt-1; ++i) printf("%d+", sol[i]);
			printf("%d=%d\n", sol[dest_cnt-1], curr_sum);
			found = 1;
		}
	}
	else
	{
		for (int i = start; i < n; ++i)
		{
			if (curr_sum + data[i] <= data[n-1])
			{
				sol[curr_cnt] = data[i];
				search(i+1, dest_cnt, curr_cnt+1, curr_sum + data[i]);
			}
			else
			{
				break;
			}
		}
	}
}

int main(void)
{
	int cas;
	scanf("%d", &cas);
	while (cas--)
	{
		scanf("%d", &n);
		for (int i = 0; i < n; ++i) scanf("%d", data+i);
		found = 0;sort(data, data+n);
		for (int i = 2; i <= n-1; ++i) search(0, i, 0, 0);
		if (!found) printf("Can't find any equations.\n");
		puts("");
	}
    return 0;
}

[fdar]

没人回答啊！！