Leetcode 525. Contiguous Array

[medium]

Contiguous Array - LeetCode

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.

[Think]

1. I was think using sliding window in this question, and hashmap would be good to notice current total sum.
2. if we found another number with the same sum, which mean they have the same 0 and 1 between them. calculate the different between these two number

3. map.put(0, -1) -> current sum equal 0, add the first one if total array equal to 0.

[Java]