poj 2479 Maximum sum

Maximum sum

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 24408		Accepted: 7404

Description

Given a set of n integers: A={a1, a2,..., an}, we define a function d(A) as below:

Your task is to calculate d(A).

Input

The input consists of T(<=30) test cases. The number of test cases (T) is given in the first line of the input.
Each test case contains two lines. The first line is an integer n(2<=n<=50000). The second line contains n integers: a1, a2, ..., an. (|ai| <= 10000).There is an empty line after each case.

Output

Print exactly one line for each test case. The line should contain the integer d(A).

Sample Input

1

10
1 -1 2 2 3 -3 4 -4 5 -5

Sample Output

13

Hint

In the sample, we choose {2,2,3,-3,4} and {5}, then we can get the answer.

Huge input,scanf is recommended.

#include <iostream>  
 using namespace std;  
  
 int array[100001], num[100001];  
 const int MIN = INT_MIN;  
  
 int main()  
 {  
    int  n;  
    int tmp, ans, i, sum;
    int cases;
    cin>>cases;  
     while(cases--)
     {  
        cin>>n;
         tmp = MIN;    sum = 0;  
         for(i = 1; i <= n; i++){  
             scanf("%d", &num[i]);  
             sum += num[i];  
             if(sum > tmp)  
                tmp = sum;  
             array[i] = tmp;  
             if(sum < 0)  
                 sum = 0;  
         }  
         tmp = ans = MIN;  
         sum = 0;  
         for(i = n; i > 1; i--){  
             sum += num[i];  
             if(sum > tmp)  
                 tmp = sum;  
             if(ans < (array[i-1]+tmp))  
                 ans = array[i-1]+tmp;  
             if(sum < 0)  
                 sum = 0;      
         }              
         cout<<ans<<endl;  
     }      
     return 0;  
 }