53. Maximum Subarray

Description

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.

More practice: If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.

Solution

/**
 * @param {number[]} nums
 * @return {number}
 */
var maxSubArray = function(nums) {
    "use strict";
    let result = Number.MIN_SAFE_INTEGER;
    let sum = 0;
    let min = Number.MAX_SAFE_INTEGER;
    for (let i = 0; i < nums.length; i++) {
        sum += nums[i];
        let tmp = Math.max(sum, sum-min);
        if (tmp > result) {
            result = tmp;
        }
        if (min > sum) {
            min = sum;
        }
    }
    return result;
};