Maximum Product Subarray

Description

Given an integer array nums, find the contiguous subarray within an array (containing at least one number) which has the largest product.

Example 1:

Input: [2,3,-2,4]
Output: 6
Explanation: [2,3] has the largest product 6.

Example 2:

Input: [-2,0,-1]
Output: 0
Explanation: The result cannot be 2, because [-2,-1] is not a subarray.

Solution(javascript)

/*
 * @lc app=leetcode id=152 lang=javascript
 *
 * [152] Maximum Product Subarray
 */

// @lc code=start
/**
 * @param {number[]} nums
 * @return {number}
 */
const maxProduct = (nums = []) => {
  if (nums.length === 0) {
    return 0
  }
  let prevMax = nums[0]
  let prevMin = nums[0]
  let max = nums[0]
  for (let i = 1; i < nums.length; i++) {
    const currentMax = Math.max(nums[i], prevMax * nums[i], prevMin * nums[i])
    const currentMin = Math.min(nums[i], prevMax * nums[i], prevMin * nums[i])
    prevMax = currentMax
    prevMin = currentMin
    if (prevMax > max) {
      max = prevMax
    }
  }
  return max
}