排序之后再剪枝，有点神

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <map>

#include <set>

#include <sstream>

#include <string>

#include <cstring>

#include <algorithm>

#include <iostream>

#define maxn 200010

#define INF 0x7fffffff

#define inf 10000000

#define ull unsigned long long

#define ll long long

using namespace std;

int a[65], n;

bool vis[65];

bool cmp(int a, int b)

{

    return a > b;

}

bool dfs(int cc, int now, int aim, int k, int cur)

{

   // printf("*****%d***%d***\n", now, cur);

    if(cur == cc) return true;

    for(int i = k; i < n; ++ i)

    {

        //if(i && !vis[i-1] && a[i] == a[i-1]) continue;

        if(!vis[i] && a[i] < now)

        {

            vis[i] = 1;

            if(dfs(cc, now-a[i], aim, i+1, cur)) return true;

            vis[i] = 0;

            if(now == aim)                       //第一个棒如果用不到，显然不能成功，直接结束

                return false;

        }

        else if(!vis[i] && a[i] == now)

        {

            vis[i] = 1;

            if(dfs(cc, aim, aim, 0, cur+1)) return true;

            vis[i] = 0;

            return false;                        //因为棒从大到小排，如果无法成功，直接结束

        }

    }

    return false;

}

int main()

{

    while(scanf("%d", &n) == 1 && n)

    {

        int _max = 0, sum = 0, ans;

        memset(vis, 0, sizeof(vis));

        for(int i = 0; i < n; ++ i)

        {

            scanf("%d", &a[i]);

            _max = max(_max, a[i]);

            sum += a[i];

        }

        sort(a, a+n, cmp);

        for(int i = _max; i <= sum; ++ i)

        {

            if(sum%i == 0 && dfs(sum/i - 1, i, i, 0, 0))

            {

                ans = i;

                break;

            }

        }

        printf("%d\n", ans);

    }

    return 0;

}