title: Find The Number Occurring Odd Number Of Times 1
signature: int findTheNumberOccurringOddNumberOfTimes1(vector<int> arr, int size) {
test_code: #include <algorithm>
  #include <assert.h>
  #include <cstdlib>
  #include <iostream>
  #include <map>
  #include <set>
  #include <string>
  #include <tuple> 
  #include <unordered_map>
  #include <vector>
  #include <math.h>
  #include <cmath>
  #include <bits/stdc++.h>
  #include <numeric>
  #include <functional>
  
  using namespace std;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(int actual, int expected){
      return actual == expected;
  }
  
  string driver(vector<int> arr, int size, int expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(arr, size), expected)){
              return "PASSED";
          }
          return "FAILED";
      }
      catch (const std::overflow_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::runtime_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::exception& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (...)
      {
          return "UNK_ERROR";
      }
  }
  
  int main() {
      string result = "";
  
      result = driver({49, 90}, 1, 49); 
      cout << "TEST-" << 0 << "..."
           <<  result
           << "\n";
  
      result = driver({-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); 
      cout << "TEST-" << 1 << "..."
           <<  result
           << "\n";
  
      result = driver({0, 1}, 1, 0); 
      cout << "TEST-" << 2 << "..."
           <<  result
           << "\n";
  
      result = driver({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); 
      cout << "TEST-" << 3 << "..."
           <<  result
           << "\n";
  
      result = driver({-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); 
      cout << "TEST-" << 4 << "..."
           <<  result
           << "\n";
  
      result = driver({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); 
      cout << "TEST-" << 5 << "..."
           <<  result
           << "\n";
  
      result = driver({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); 
      cout << "TEST-" << 6 << "..."
           <<  result
           << "\n";
  
      result = driver({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); 
      cout << "TEST-" << 7 << "..."
           <<  result
           << "\n";
  
      result = driver({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); 
      cout << "TEST-" << 8 << "..."
           <<  result
           << "\n";
  
      result = driver({11, 4, 98, 38, 20, 41, 1, 8}, 7, 11); 
      cout << "TEST-" << 9 << "..."
           <<  result
           << "\n";
  
      return 0;
  }
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;
  }