Maximum Length Substring With Two Occurrences - Sliding Window [JS]

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Description 

Solution: Sliding Window

Maintain a sliding window where no character has more than 2 occurances.
Keep track of the count of characters in the window.
If a count exceeds 2, move the left pointer up until the count is no longer exceeding 2.
Record and return the maximum window length.

Time Complexity: O(n)
Space Complexity: O(1)

var maximumLengthSubstring = function(s) {
  let n = s.length, count = Array(26).fill(0), ans = 0;
  for (let j = 0, i = 0; j < n; j++) {
    count[s.charCodeAt(j) - 97]++;
    while (count[s.charCodeAt(j) - 97] > 2) {
      count[s.charCodeAt(i) - 97]--;
      i++;
    }
    ans = Math.max(ans, j - i + 1);
  }
  return ans;
};
Location: Auckland, New Zealand

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