title: First Element Occurring K Times Array
signature: pub fn first_element_occurring_k_times_array(arr: Vec<i32>, n: i32, k: 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>, n: i32, k: i32, expected: i32)->String{
      if validate_solution(PLACEHOLDER_FN_NAME(arr, n, k), expected) {
        return "PASSED".to_string();
      };
      return "FAILED".to_string();
  
  }
  
  fn main() {
      println!("TEST-0...{}", driver(
        Vec::from([2, 3, 4, 4, 7, 18, 20, 23, 27, 30, 31, 31, 32, 35, 36, 43, 45, 46, 49, 50, 53, 55, 59, 60, 64, 64, 65, 68, 78, 80, 80, 85, 95]), 30, 2, 
        4
      ));
      
      println!("TEST-1...{}", driver(
        Vec::from([-26, 32, 36, 6, 64, 24, -28, 96]), 6, 3, 
        -1
      ));
      
      println!("TEST-2...{}", driver(
        Vec::from([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]), 15, 7, 
        -1
      ));
      
      println!("TEST-3...{}", driver(
        Vec::from([38, 40, 43, 70, 20, 40, 95, 96, 81, 82]), 9, 1, 
        38
      ));
      
      println!("TEST-4...{}", driver(
        Vec::from([-68, -8, -8, 16, 24, 54]), 3, 2, 
        -8
      ));
      
      println!("TEST-5...{}", driver(
        Vec::from([1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1]), 6, 4, 
        0
      ));
      
      println!("TEST-6...{}", driver(
        Vec::from([13, 18, 19, 28, 31, 34, 49, 49, 53, 57, 58, 62, 75, 76, 77, 78, 80, 84, 84, 85, 87, 91, 98, 99]), 20, 2, 
        49
      ));
      
      println!("TEST-7...{}", driver(
        Vec::from([-4, 24, -86, -84, 30, -16, 12, -92, -68, 22]), 6, 5, 
        -1
      ));
      
      println!("TEST-8...{}", driver(
        Vec::from([0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1]), 8, 10, 
        -1
      ));
      
      println!("TEST-9...{}", driver(
        Vec::from([55, 44, 75, 97, 25, 65, 76, 53, 20, 78, 25, 59, 61, 29, 81, 35, 15, 78, 41, 44, 31, 33, 39, 93, 26, 67]), 23, 20, 
        -1
      ));
      
  }
source_py: def first_element_occurring_k_times_array(arr, n, k):
      count_map = {
          
      }
      for i in range(0, n):
          if (arr[i] in count_map.keys()):
              count_map[arr[i]] += 1
          else:
              count_map[arr[i]] = 1
          i += 1
      for i in range(0, n):
          if (count_map[arr[i]] == k):
              return arr[i]
          i += 1
      return (- 1)
source_cpp: int first_element_occurring_k_times_array(vector<int> arr, int n, int k) {
    unordered_map < int, int > count_map;
    for ( int i = 0;
    i < n;
    i ++ ) count_map [ arr [ i ] ] ++;
    for ( int i = 0;
    i < n;
    i ++ ) if ( count_map [ arr [ i ] ] == k ) return arr [ i ];
    return - 1;
  }