1
/**
2
 * @param {number[]} nums
3
 * @return {number}
4
 */
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var specialArray = function (nums) {
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  // step 1: sort
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  nums = nums.sort((a, b) => a - b);
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  // step 2: search
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  for (let i = nums.length; i >= 0; i--) {
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    // found:
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    if (bs(nums, i)) return i;
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  }
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  // not found:
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  return -1;
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};
16

17
function bs(array, target) {
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  let left = 0;
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  let right = array.length - 1;
20

21
  while (left <= right) {
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    const mid = Math.floor((left + right) / 2);
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    if (array[mid] < target) left = mid + 1;
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    else right = mid - 1;
25
  }
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27
  const greaterThanTarget = array.length - left;
28

29
  return greaterThanTarget === target;
30
}