Description
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 <= 105nums[i]is either0or1.
Code
class Solution {
public:
int findMaxLength(vector<int>& nums) {
unordered_map<int, int> mp;
mp[0] = -1;
int sum = 0, maxLen = 0;
for(int i = 0; i < nums.size(); i++) {
sum += nums[i] == 1 ? 1 : -1;
if(mp.count(sum)) maxLen = max(maxLen, i - mp[sum]);
else mp[sum] = i;
}
return maxLen;
}
};