UVa 10304 Optimal Binary Search Tree / 区间DP

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn = 255;
int a[maxn];
int sum[maxn];
int dp[maxn][maxn];

int dfs(int l, int r)
{
	if(dp[l][r] != -1)
		return dp[l][r];
	if(l > r)
		return 0;
	dp[l][r] = 999999999;
	for(int i = l; i <= r; i++)
	{
		dp[l][r] = min(dp[l][r], dfs(l, i-1)+dfs(i+1, r)+sum[r]-sum[l-1]-a[i]);
	}
	return dp[l][r];
}
int main()
{
	int n;
	while(scanf("%d", &n) != EOF)
	{
		for(int i = 1; i <= n; i++)
		{
			scanf("%d", &a[i]);
			sum[i] = sum[i-1]+a[i];
		}
		memset(dp, -1, sizeof(dp));
		printf("%d\n", dfs(1, n));
	}
	return 0;
}