title: Binary Search
signature: function binarySearch(arr: Array<number>, l: number, r: number, x: number): number {
test_code: 
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function convertToString(value: any): string{
      return JSON.stringify(value, function (key, val) {
          if (val instanceof Set) {
              return Array.from(val);
          } return val;});
  }
  
  function validateSolution(actual: number, expected: number): boolean {
      return convertToString(actual) === convertToString(expected);
  }
  
  function driver(arr: Array<number>, l: number, r: number, x: number, expected:number): string {
      try{
          if (validateSolution(PLACEHOLDER_FN_NAME(arr, l, r, x),expected)){
              return "PASSED";
          }
          return "FAILED";
      } catch (error) {
        return error.name;
      }
      
  }
      
  function main(){
    let result = '';
    result = driver([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);
    console.log(`TEST-0...${result}`);
  
    result = driver([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);
    console.log(`TEST-1...${result}`);
  
    result = driver([0, 1], 1, 1, 1, 1);
    console.log(`TEST-2...${result}`);
  
    result = driver([28, 84, 40, 81], 2, 2, 2, -1);
    console.log(`TEST-3...${result}`);
  
    result = driver([-66, -62, -60, -56, -56, -2, 40, 44, 50, 74, 82, 94], 8, 6, 8, -1);
    console.log(`TEST-4...${result}`);
  
    result = driver([1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1], 7, 7, 10, -1);
    console.log(`TEST-5...${result}`);
  
    result = driver([15, 26, 31, 36, 36, 61, 68, 72, 75, 79, 82, 98], 6, 7, 8, -1);
    console.log(`TEST-6...${result}`);
  
    result = driver([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);
    console.log(`TEST-7...${result}`);
  
    result = driver([0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1], 12, 10, 6, -1);
    console.log(`TEST-8...${result}`);
  
    result = driver([81, 47], 1, 1, 1, -1);
    console.log(`TEST-9...${result}`);
  
  };
  
  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;
  }