hdu 1231 DP

超级简单的DP  不过那个判断要注意下。。。我开始用sum = -sum（abs（a[i]））来判断一直错。。。。。。

ac代码如下：

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;

int main(){
	int K, a[10010], first, pos, end, startfrom, dp[10010], flog;

	while( scanf( "%d", &K ) && K ){
		memset( a, 0, sizeof( a ) );
		memset( dp, 0, sizeof( dp ) );
		flog = 1;
		for( int i = 0; i < K; i++ ){
			scanf( "%d", a + i );
			if( a[i] >= 0 ){
				flog = 0;
			}
		}
		if( flog ){
			cout << 0 << " " << a[0] << " " << a[K-1] << endl;
			continue;
		}
		startfrom = a[0];
		first = end = pos = 0;
		dp[0] = a[0];
		for( int i = 1; i < K; i++ ){
			if( startfrom + a[i] < a[i] ){
				startfrom = a[i];
				pos = i;
			}else{
				startfrom += a[i];
			}
			if( dp[i-1] < startfrom ){
				first = pos;
				end = i;
				dp[i] = startfrom;
			}else{
				dp[i] = dp[i-1];
			}
		}
		cout << dp[K-1] << " " << a[first] << " " << a[end] << endl;
	}
	return 0;
}