10.maximum-subarray.js

// https://leetcode.com/problems/maximum-subarray/
// Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

// A subarray is a contiguous part of an array.

// Example 1:

// Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
// Output: 6
// Explanation: [4,-1,2,1] has the largest sum = 6.
// Example 2:

// Input: nums = [1]
// Output: 1
// Example 3:

// Input: nums = [5,4,-1,7,8]
// Output: 23


// Constraints:

// 1 <= nums.length <= 105
// -104 <= nums[i] <= 104


// Follow up: If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.
/**
 * @param {number[]} nums
 * @return {number}
 */
var maxSubArray = function (nums) {
    let currSum = -Infinity;
    let maxSum = -Infinity;
    for (let i = 0; i < nums.length; i++) {
        currSum = Math.max(0, currSum);
        currSum += nums[i];
        maxSum = Math.max(maxSum, currSum);
    }
    return maxSum;
};