title: Check Exist Two Elements Array Whose Sum Equal Sum Rest Array
signature: function checkExistTwoElementsArrayWhoseSumEqualSumRestArray(arr, n) {
source_py: def check_exist_two_elements_array_whose_sum_equal_sum_rest_array(arr, n):
      s = set()
      sum = 0
      for i in range(n):
          sum += arr[i]
      if ((sum % 2) != 0):
          return False
      sum = (sum / 2)
      for i in range(n):
          val = (sum - arr[i])
          if (arr[i] not in s):
              s.add(arr[i])
          if (val in s):
              print('Pair elements are', arr[i], 'and', int(val))
source_cpp: bool check_exist_two_elements_array_whose_sum_equal_sum_rest_array(vector<int> arr, int n) {
    int sum = 0;
    for ( int i = 0;
    i < n;
    i ++ ) sum += arr [ i ];
    if ( sum % 2 != 0 ) return false;
    sum = sum / 2;
    unordered_set < int > s;
    for ( int i = 0;
    i < n;
    i ++ ) {
      int val = sum - arr [ i ];
      if ( s . find ( val ) != s . end ( ) ) {
        return true;
      }
      s . insert ( arr [ i ] );
    }
    return false;
  }