525. Contiguous Array

Problem

Given a binary array nums, return **the maximum length of a contiguous subarray with an equal number of *0* and **1.

  Example 1:

Input: nums = [0,1] Output: 2 Explanation: [0, 1] is the longest contiguous subarray with an equal number of 0 and 1. 

Example 2:

Input: nums = [0,1,0] Output: 2 Explanation: [0, 1] (or [1, 0]) is a longest contiguous subarray with equal number of 0 and 1. 

  Constraints:

• 1 <= nums.length <= 105

• nums[i] is either 0 or 1.

Solution

/** * @param {number[]} nums * @return {number} */ var findMaxLength = function(nums) { var map = {}; var count = 0; var max = 0; map[0] = -1; for (var i = 0; i < nums.length; i++) { count += (nums[i] === 1 ? 1 : -1); if (map[count] !== undefined) { max = Math.max(max, i - map[count]) } else { map[count] = i; } } return max; }; 

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).