https://www.luogu.com.cn/record/138164217

#include <algorithm>
#include <cstring>
#include <iostream>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)

bool used[70], found = 0;
int n, a[70], maxn = 0, sum = 0, len, num, tmp;
int cmp(const int &x, const int &y) {return x > y;}
void dfs(int dep, int last, int rest) {
	if(dep == num) {
		found = 1;
		return ;
	}
	if(rest == 0) rep(i, n) if(!used[i]) {
		used[i] = 1;
		dfs(dep + 1, i, len - a[i]);
		break;
	}
	for(int i = last + 1; i < n; i++) if(!used[i] && rest >= a[i]) {
		used[i] = 1;
		dfs(dep, i, rest - a[i]);
		used[i] = 0;
		tmp = i;
		while(i < n - 1 && a[i] == a[tmp]) i++;
		if(i == n - 1) return ;
	}
}
int main() {
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n;
	rep(i, n) {
		cin >> a[i];
		maxn = max(maxn, a[i]);
		sum += a[i];
	}
	sort(a, a + n, cmp);
	for(int i = maxn; i <= sum; i++) if(sum % i == 0) {
		memset(used, 0, sizeof(used));
		len = i, used[0] = 1, found = 0, num = sum / len;
		dfs(1, 0, len - a[0]);
		if(found) {
			cout << len;
			return 0;
		}
	}
}