LeetCode 53. Maximum Subarray (javascript)

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

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 <= 3 * 104
• -105 <= nums[i] <= 105

Idea:

Dynamic Programing

• Base case: dp[0] = nums[0];
• dp[i] = Math.max(dp[i – 1] + nums[i], nums[i]);

Solution:

/**
 * @param {number[]} nums
 * @return {number}
 */
var maxSubArray = function(nums) {
    // dp[i] the largest sum of subarray in nums[0...i]
    let dp = new Array(nums.length);
    // basic case:
    dp[0] = nums[0];
    for (let i = 1; i < nums.length; i++) {
        dp[i] = Math.max(dp[i - 1] + nums[i], nums[i]);
    }
    return Math.max(...dp);
};