CareerCup

private static int countPossibleMatches(int[] array, int left, int right, int min, int max) {
        if (right < left) {
            return 0;
        } else if (right == left) {
            return (array[left] >= min && array[left] <= max? 1 : 0);
        } else {
            int middle = (left + right) / 2;
            int count = (array[middle] >= min && array[middle] <= max ? 1 : 0);
            count += countPossibleMatches(array, left, middle - 1, min, Math.min(array[middle], max));
            count += countPossibleMatches(array, middle + 1, right, Math.max(array[middle], min), max);
            return count;
        }
    }

    static int countPossibleMatches(int[] array) {
        return countPossibleMatches(array, 0, array.length - 1, Integer.MIN_VALUE, Integer.MAX_VALUE);
    }

Why no one is commenting on their code or explaining it, it's really frustrating.
Don't get the point of just pasting a block of code

static int countPossibleMatches(int[] array, int left, int right, int min, int max) {
        if (right < left) {
            return 0;
        } else if (right == left) {
            return (array[left] >= min && array[left] <= max? 1 : 0);
        } else {
            int middle = (left + right) / 2;
            int count = (array[middle] >= min && array[middle] <= max ? 1 : 0);
            count += countPossibleMatches(array, left, middle - 1, min, Math.min(array[middle], max));
            count += countPossibleMatches(array, middle + 1, right, Math.max(array[middle], min), max);
            return count;
        }
    }

    static int countPossibleMatches(int[] array) {
        return countPossibleMatches(array, 0, array.length - 1, Integer.MIN_VALUE, Integer.MAX_VALUE);
    }

Isn't it LIS(longest increasing subsequence)

This will produce unstable search depending on how you define midpoint. If it is with Math.ceil() then we can find 5 but not 4. However if it is with Math.round() you can find 4 but not 5.

function binarySearch(array, elm){
  function binarySearchIter(arr, index){
    let midpoint = Math.round(arr.length / 2); 
    let left = arr.slice(0, midpoint); 
    let right = arr.slice(midpoint); 
    if (arr[midpoint] === elm){
      return index + midpoint; 
    }
    else if (arr.length <= 1){
     return -1; 
   }
   else {
     let leftRes = binarySearchIter(left, index);
     let rightRes = binarySearchIter(right, index + midpoint); 
     return leftRes > -1 ? leftRes : rightRes; 
   }
   
  }
  return binarySearchIter(array, 0);

}