title: Non Repeating Element
signature: int nonRepeatingElement(vector<int> arr, int n) {
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 n, int expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(arr, n), 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({1, 2, 3, 4, 6, 6, 7, 9, 10, 13, 16, 23, 30, 32, 36, 42, 42, 43, 44, 47, 48, 48, 49, 52, 52, 53, 55, 56, 58, 59, 60, 60, 63, 67, 68, 68, 74, 75, 76, 80, 81, 81, 83, 83, 86, 87, 91, 92, 97}, 47, 1); 
      cout << "TEST-" << 0 << "..."
           <<  result
           << "\n";
  
      result = driver({-96, -46, -86, 56, -72, 50, 18, 8, 50}, 8, -96); 
      cout << "TEST-" << 1 << "..."
           <<  result
           << "\n";
  
      result = driver({0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 14, -1); 
      cout << "TEST-" << 2 << "..."
           <<  result
           << "\n";
  
      result = driver({19, 10, 49, 40, 34, 21, 63, 51}, 5, 19); 
      cout << "TEST-" << 3 << "..."
           <<  result
           << "\n";
  
      result = driver({-96, -96, -90, -88, -88, -84, -80, -76, -68, -64, -64, -52, -52, -52, -52, -50, -50, -48, -48, -40, -32, -26, -24, -22, -20, -14, -12, 0, 6, 8, 10, 20, 24, 28, 34, 36, 54, 60, 60, 60, 68, 74, 74, 74, 84, 88, 94}, 27, -90); 
      cout << "TEST-" << 4 << "..."
           <<  result
           << "\n";
  
      result = driver({1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0}, 19, -1); 
      cout << "TEST-" << 5 << "..."
           <<  result
           << "\n";
  
      result = driver({1, 2, 3, 10, 15, 21, 28, 36, 41, 44, 45, 47, 72, 77, 77, 79, 85}, 15, 1); 
      cout << "TEST-" << 6 << "..."
           <<  result
           << "\n";
  
      result = driver({42, -84, 42, 36, -10, 24, -62, 60}, 7, -84); 
      cout << "TEST-" << 7 << "..."
           <<  result
           << "\n";
  
      result = driver({0, 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, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 35, -1); 
      cout << "TEST-" << 8 << "..."
           <<  result
           << "\n";
  
      result = driver({2, 21, 42, 92, 65, 62, 75, 43, 81, 17, 92, 86, 37, 63, 27, 97, 24, 61, 85, 49, 84, 7, 14, 19, 60, 55, 68, 79, 8, 12, 75, 12, 92, 79, 42}, 27, 2); 
      cout << "TEST-" << 9 << "..."
           <<  result
           << "\n";
  
      return 0;
  }
source_py: def non_repeating_element(arr, n):
      for i in range(n):
          j = 0
          while (j < n):
              if ((i != j) and (arr[i] == arr[j])):
                  break
              j += 1
          if (j == n):
              return arr[i]
      return (- 1)
source_cpp: int non_repeating_element(vector<int> arr, int n) {
    for ( int i = 0;
    i < n;
    i ++ ) {
      int j;
      for ( j = 0;
      j < n;
      j ++ ) if ( i != j && arr [ i ] == arr [ j ] ) break;
      if ( j == n ) return arr [ i ];
    }
    return - 1;
  }