Last Occurrence of Element

function lastOccurrence(nums, target) {
  let left = 0, right = nums.length - 1, ans = -1;
  while (left <= right) {
    const mid = Math.floor((left + right) / 2);
    if (nums[mid] === target) {
      ans = mid;
      left = mid + 1;
    } else if (nums[mid] < target) left = mid + 1;
    else right = mid - 1;
  }
  return ans;
}
                  

Explanation: When target is found, search right side to get last index.

⏱ O(log n) | 💾 O(1)