title: Binary Search
signature: pub fn binary_search(arr: Vec<i32>, l: i32, r: i32, x: i32) -> i32 {
test_code: use std::collections::HashMap;
  use std::collections::HashSet;
  use std::cmp::*;
  use std::collections::*;
  use std::fmt::*; 
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  pub fn validate_solution(actual: i32, expected: i32)->bool{
  return actual==expected
  }
  pub fn driver(arr: Vec<i32>, l: i32, r: i32, x: i32, expected: i32)->String{
      if validate_solution(PLACEHOLDER_FN_NAME(arr, l, r, x), expected) {
        return "PASSED".to_string();
      };
      return "FAILED".to_string();
  
  }
  
  fn main() {
      println!("TEST-0...{}", driver(
        Vec::from([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
      ));
      
      println!("TEST-1...{}", driver(
        Vec::from([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
      ));
      
      println!("TEST-2...{}", driver(
        Vec::from([0, 1]), 1, 1, 1, 
        1
      ));
      
      println!("TEST-3...{}", driver(
        Vec::from([28, 84, 40, 81]), 2, 2, 2, 
        -1
      ));
      
      println!("TEST-4...{}", driver(
        Vec::from([-66, -62, -60, -56, -56, -2, 40, 44, 50, 74, 82, 94]), 8, 6, 8, 
        -1
      ));
      
      println!("TEST-5...{}", driver(
        Vec::from([1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1]), 7, 7, 10, 
        -1
      ));
      
      println!("TEST-6...{}", driver(
        Vec::from([15, 26, 31, 36, 36, 61, 68, 72, 75, 79, 82, 98]), 6, 7, 8, 
        -1
      ));
      
      println!("TEST-7...{}", driver(
        Vec::from([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
      ));
      
      println!("TEST-8...{}", driver(
        Vec::from([0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1]), 12, 10, 6, 
        -1
      ));
      
      println!("TEST-9...{}", driver(
        Vec::from([81, 47]), 1, 1, 1, 
        -1
      ));
      
  }
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;
  }