title: Count Natural Numbers Whose Permutation Greater Number
signature: int countNaturalNumbersWhosePermutationGreaterNumber(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(int n, int expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(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(69, 48); 
      cout << "TEST-" << 0 << "..."
           <<  result
           << "\n";
  
      result = driver(72, 48); 
      cout << "TEST-" << 1 << "..."
           <<  result
           << "\n";
  
      result = driver(88, 52); 
      cout << "TEST-" << 2 << "..."
           <<  result
           << "\n";
  
      result = driver(7, 7); 
      cout << "TEST-" << 3 << "..."
           <<  result
           << "\n";
  
      result = driver(66, 45); 
      cout << "TEST-" << 4 << "..."
           <<  result
           << "\n";
  
      result = driver(34, 28); 
      cout << "TEST-" << 5 << "..."
           <<  result
           << "\n";
  
      result = driver(23, 20); 
      cout << "TEST-" << 6 << "..."
           <<  result
           << "\n";
  
      result = driver(37, 31); 
      cout << "TEST-" << 7 << "..."
           <<  result
           << "\n";
  
      result = driver(33, 27); 
      cout << "TEST-" << 8 << "..."
           <<  result
           << "\n";
  
      result = driver(21, 18); 
      cout << "TEST-" << 9 << "..."
           <<  result
           << "\n";
  
      return 0;
  }
source_py: def count_natural_numbers_whose_permutation_greater_number(n):
      result = 0
      for i in range(1, 10):
          s = []
          if (i <= n):
              s.append(i)
              result += 1
          while (len(s) != 0):
              tp = s[(- 1)]
              s.pop()
              for j in range((tp % 10), 10):
                  x = ((tp * 10) + j)
                  if (x <= n):
                      s.append(x)
                      result += 1
      return result
source_cpp: int count_natural_numbers_whose_permutation_greater_number(int n) {
    int result = 0;
    for ( int i = 1;
    i <= 9;
    i ++ ) {
      stack < int > s;
      if ( i <= n ) {
        s . push ( i );
        result ++;
      }
      while ( ! s . empty ( ) ) {
        int tp = s . top ( );
        s . pop ( );
        for ( int j = tp % 10;
        j <= 9;
        j ++ ) {
          int x = tp * 10 + j;
          if ( x <= n ) {
            s . push ( x );
            result ++;
          }
        }
      }
    }
    return result;
  }