In this problem, you’re given an array of sorted integers in which all of the integers, except one, appears twice. Your task is to find the single integer that appears only once. The solution should have a time complexity of O(logn) or better and a space complexity of O(1) .

find-single-non-duplicate.js

export function singleNonDuplicate(nums) {
  let start = 0;
  let end = nums.length - 1;

  while (start < end) {
    let mid = Math.floor((end - start) / 2) + start;
    if (mid % 2 !== 0) {
      mid -= 1;
    }
    if (nums[mid] !== nums[mid + 1]) {
      end = mid;
    } else {
      start = mid + 2;
    }
  }

  return nums[start];
}