title: Binary Search
signature: function binarySearch($arr, $l, $r, $x) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return serialize($actual) == serialize($expected);
  }
  
  function driver($arr, $l, $r, $x, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($arr, $l, $r, $x), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        array(3, 4, 4, 8, 9, 13, 13, 15, 18, 27, 30, 32, 42, 48, 50, 52, 56, 66, 69, 69, 77, 84, 84, 93), 19, 12, 22, 
        -1));
      
      printf("TEST-1...%s\n",driver(
        array(52, -58, -22, -80, 44, -52, -34, 94, -34, -74, 42, 60, -62, 70, 98, 32, 10, 94, 26, 56, -48, -50, 42, 2, 46, 28, -68, -16, -96, -12, 66, -46, 74, -60, -52, 28, -92, -78, 32, 28, 16, 34, 30, -60, -14), 40, 35, 44, 
        -1));
      
      printf("TEST-2...%s\n",driver(
        array(0, 1), 1, 1, 1, 
        1));
      
      printf("TEST-3...%s\n",driver(
        array(28, 84, 40, 81), 2, 2, 2, 
        -1));
      
      printf("TEST-4...%s\n",driver(
        array(-66, -62, -60, -56, -56, -2, 40, 44, 50, 74, 82, 94), 8, 6, 8, 
        -1));
      
      printf("TEST-5...%s\n",driver(
        array(1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1), 7, 7, 10, 
        -1));
      
      printf("TEST-6...%s\n",driver(
        array(15, 26, 31, 36, 36, 61, 68, 72, 75, 79, 82, 98), 6, 7, 8, 
        -1));
      
      printf("TEST-7...%s\n",driver(
        array(0, -82, -94, 48, 48, -96, 14, 66, 76, -30, 86, 28, -28, -66, -64, 92, -94, -66, 86, 26, 8, 94, -82, -80, 4, -26, 76, -46, 72, 88, -6, 8, -30, 40, -88, 2, -40, -98, -22, -20, 4, -12, 54, -20, -36, 12), 38, 33, 39, 
        -1));
      
      printf("TEST-8...%s\n",driver(
        array(0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1), 12, 10, 6, 
        -1));
      
      printf("TEST-9...%s\n",driver(
        array(81, 47), 1, 1, 1, 
        -1));
      
  }
  
  main();
  ?>
source_py: def binary_search(arr, l, r, x):
      if (r >= l):
          mid = (l + ((r - l) // 2))
          if (arr[mid] == x):
              return mid
          elif (arr[mid] > x):
              return binary_search(arr, l, (mid - 1), x)
          else:
              return binary_search(arr, (mid + 1), r, x)
      else:
          return (- 1)
source_cpp: int binary_search(vector<int> arr, int l, int r, int x) {
    if ( r >= l ) {
      int mid = l + ( r - l ) / 2;
      if ( arr [ mid ] == x ) return mid;
      if ( arr [ mid ] > x ) return binary_search ( arr, l, mid - 1, x );
      return binary_search ( arr, mid + 1, r, x );
    }
    return - 1;
  }