木棒POJ1011

木棒POJ1011

思路

题干在这：POJ1011
按着《算法竞赛进阶指南》的代码写的，熟悉一下深搜和剪枝

ac代码

#include<cstdio>
#include<algorithm>
#include<iostream>
using namespace std;
int a[100], v[100], n, len, cnt;
bool dfs(int stick, int cab, int last) {
	if (stick > cnt)
		return true;
	if (cab == len)
		return dfs(stick + 1, 0, 1);
	int fail = 0;
	for (int i = last; i <= n; i++) {
		if (!v[i] && cab + a[i] <= len && a[i] != fail) {
			v[i] = 1;
			if (dfs(stick, cab + a[i], i + 1))
				return true;
			fail = a[i];
			v[i] = 0;
			if (cab == 0)
				return false;
		}
	}
	return false;
}
int main() {
	while (cin >> n && n) {
		int sum = 0, val = 0;
		for (int i = 1; i <= n; i++) {
			scanf_s("%d", a + i);
			sum += a[i];
			val = max(val, a[i]);
		}
		sort(a + 1, a + n + 1);
		reverse(a + 1, a + n + 1);
		for (len = val; len <= sum; len++) {
			if (sum % len)
				continue;
			cnt = sum / len;
			memset(v, 0, sizeof(v));
			if (dfs(1, 0, 1))
				break;
		}
		cout << len << endl;
	}
}