title: Find The Number Occurring Odd Number Of Times 1
signature: function findTheNumberOccurringOddNumberOfTimes1($arr, $size) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return serialize($actual) == serialize($expected);
  }
  
  function driver($arr, $size, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($arr, $size), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        array(49, 90), 1, 
        49));
      
      printf("TEST-1...%s\n",driver(
        array(-96, 94, 92, -24, 48, 54, -30, -86, 28, -18, 12, -64, -36, 68, 68, -78, -6, 30, -84, 20, 52, -36, 40, -62, 90, -48, 86, 98, 12, 44, 98, -66, 52, 34, 36, 76, -50, -20, -20, -20), 39, 
        -96));
      
      printf("TEST-2...%s\n",driver(
        array(0, 1), 1, 
        0));
      
      printf("TEST-3...%s\n",driver(
        array(79, 55, 18, 99, 38, 93, 19, 49, 21, 74, 16, 76, 82, 52, 86, 17, 42, 9, 6, 63, 1, 40, 75, 59, 41, 81), 23, 
        79));
      
      printf("TEST-4...%s\n",driver(
        array(-90, -84, -82, -68, -66, -66, -60, -60, -48, -44, -36, -34, -30, -16, -14, -12, -10, -6, 2, 10, 10, 14, 22, 26, 30, 34, 46, 50, 52, 62, 64, 64, 66, 72, 74, 78, 78, 82, 84, 88, 92), 23, 
        -90));
      
      printf("TEST-5...%s\n",driver(
        array(1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1), 18, 
        1));
      
      printf("TEST-6...%s\n",driver(
        array(2, 4, 5, 7, 7, 18, 18, 23, 23, 25, 25, 31, 41, 43, 45, 46, 52, 52, 55, 64, 69, 69, 80, 81, 84, 90, 91, 93, 94, 94, 94, 94, 96, 98, 99), 20, 
        2));
      
      printf("TEST-7...%s\n",driver(
        array(86, 66, -8, 2, -18, -22, 38, 4, -38, -54, 78, 64, 78, 20, -32, 84, -70, 66, -46, 12, -12, 8, 44, 14, 20), 20, 
        86));
      
      printf("TEST-8...%s\n",driver(
        array(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, 1, 1, 1, 1, 1), 21, 
        0));
      
      printf("TEST-9...%s\n",driver(
        array(11, 4, 98, 38, 20, 41, 1, 8), 7, 
        11));
      
  }
  
  main();
  ?>
source_py: def find_the_number_occurring_odd_number_of_times_1(arr, size):
      Hash = dict()
      for i in range(size):
          Hash[arr[i]] = (Hash.get(arr[i], 0) + 1)
      for i in Hash:
          if ((Hash[i] % 2) != 0):
              return i
      return (- 1)
source_cpp: int find_the_number_occurring_odd_number_of_times_1(vector<int> arr, int size) {
    unordered_map < int, int > hash;
    for ( int i = 0;
    i < size;
    i ++ ) {
      hash [ arr [ i ] ] ++;
    }
    for ( auto i : hash ) {
      if ( i . second % 2 != 0 ) {
        return i . first;
      }
    }
    return - 1;
  }