洛谷 P1120 小木棍

题意简述

给出n个数，求最小的l，使n个数可分成若干组，每组和都为l。

题解思路

暴力搜索+剪枝

代码

#include <cstdio>
#include <cstdlib>
#include <algorithm>
using namespace std;
int n, sum, minn, maxx;
int t[70];
void dfs(int gs, int last, int sy, int qb)
{
	if (gs == 0)
	{
		printf("%d\n", qb);
		exit(0);
	}
	if (sy == 0)
		dfs(gs - 1, maxx, qb, qb);
	bool flag = true;
	for (int i = min(last, sy); i >= 1; --i)
		if (t[i] > 0)
		{
			flag = false;
			t[i] --;
			dfs(gs, i, sy - i, qb);
			t[i] ++;
			if (i == sy || sy == qb)
				return;
		}
	if (flag)
		return;
}
int main()
{
	scanf("%d", &n);
	for (int i = 1; i <= n; ++i)
	{
		int x;
		scanf("%d", &x);
		if (x <= 50)
		{
			t[x] ++;
			sum += x;
			maxx = max(maxx, x);
		}
	}
	for (int i = maxx; i <= sum; ++i)
		if (sum % i == 0)
			dfs(sum / i, maxx, i, i);
}