53. Maximum Subarray

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.

EXPLANATION:

这是一个之前就有的算法,具体可以查看这个链接.

SOLUTION:

public int maxSubArray(int[] nums) {//Time limit 
        int max = nums[0];
        for(int i = 0 ;i<nums.length;i++){
            for(int j = 0;j<nums.length;j++){
                if(i+j<nums.length){
                    int sum = 0;
                    for(int k = i; k<=i+j;k++){
                        sum = sum + nums[k];
                    }
                    max = Math.max(max,sum);
                }
            }
        }
        return max;
    }

public int maxSubArray(int[] nums) {
        int global = nums[0];
        int local = nums[0];
        for(int i=1;i<nums.length;i++)
        {
            local = Math.max(nums[i],local+nums[i]);
            global = Math.max(local,global);
        }
        return global;
    }