hdu 1300 简单dp

水的不能再水了，合理利用下前缀和

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define MAX 107

using namespace std;

int t,n;
int a[MAX];
int c[MAX];
int dp[MAX];
int sum[MAX];

int main ( )
{
    scanf ( "%d" , &t );
    while ( t-- )
    {
        scanf ( "%d" , &n );
        sum[0] = 0;
        for ( int i = 1 ; i <= n ; i++ ) 
        {
            scanf ( "%d%d" , &a[i] , &c[i] );
            sum[i] = sum[i-1] + a[i];
        }
        memset ( dp , 0x3f , sizeof ( dp ) );
        dp[0] = 0;
        for ( int i = 1 ; i <= n ; i++ )
            for ( int j = 0 ; j < i ; j++ )
                dp[i] = min ( dp[i] , dp[j] + c[i]*(sum[i]-sum[j]+10) );
        printf ( "%d\n" , dp[n] );
    }
}