LeetCode: Maximum Subarray

Problem:

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [−2,1,−3,4,−1,2,1,−5,4],
the contiguous subarray [4,−1,2,1] has the largest sum = 6.

考虑只有负数的数组的最大子数组和，时间复杂度O(n)。

class Solution {
public:
   int maxSubArray(int A[], int n) {
       // Start typing your C/C++ solution below
       // DO NOT write int main() function
       if (A == NULL || n == 0)
           return 0;
       int maxSum = A[0];
       int endSum = 0;
       for (int i = 0; i < n; ++i)
       {
           if (endSum >= 0)
           {
                endSum += A[i];
           }
           else
           {
                endSum = A[i];
           }
 
           if(maxSum < endSum)
           {
                maxSum = endSum;
           }
           
       }
       return maxSum;
    }
};