Maximum Subarray

1. Title

Maximum Subarray

2. Http address

https://leetcode.com/problems/maximum-subarray/

3. The question

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.

 4 My code(AC)

    public int maxSubArray(int[] nums) {
     
        if ( nums == null || nums.length == 0)
            return 0;
        int contiguousMax[] = new int[nums.length];
        contiguousMax[0] = nums[0];
        for(int i = 1 ; i < nums.length; i++)
        {
            contiguousMax[i] = Math.max(contiguousMax[i-1] + nums[i], nums[i]);
        }
        int opt_cur = nums[0];
        for(int i = 1; i < nums.length; i++)
        {
            opt_cur = Math.max(opt_cur, contiguousMax[i]);
        }
        return opt_cur;
    }
    
    // Accepted
    public int maxSubArrayTwo(int[] nums) {
        
        if ( nums == null || nums.length == 0)
            return 0;

        int opt_cur = nums[0];
        int contiguousMax = nums[0];
        for(int i = 1; i < nums.length; i++)
        {
            contiguousMax = Math.max(contiguousMax + nums[i], nums[i]);
            opt_cur = Math.max(opt_cur, contiguousMax);
        }
        return opt_cur;
    }