BinarySearch

public int binarySearch(int []num, int target) {
  int min = 0;
  int max = num.length - 1;
  
  while (min <= max) {
    int mid = min + (max - min)/2;
    if (num[mid] == target) {
      return mid;
    } else if (target < num[mid]) {
      max = mid - 1;
    } else {
      min = mid + 1;
    }
  }
  
  return -1;
}