[백준 1065] 한수 (C/C++)

#include <stdio.h>
#include <iostream>
#include <set>
#include <map>
#include <queue>
#include <vector>
#include <string>
#include <math.h>
#include <algorithm>
using namespace std;
 
string num;
 
int main(void)
{
//    freopen("B1065_input.txt", "r", stdin);
    
    cin >> num;
    
    if(num.size() <= 2)
    {
        cout << num << endl;
    }
    else
    {
        int ans = 99;
        
        for(int i = 100; i <= stoi(num); i++)
        {
            string tempNum = to_string(i);
            int diff = tempNum[0]-tempNum[1];
            bool flag = true;
            
            for(int j = 0; j < tempNum.size()-1; j++)
            {
                if(tempNum[j]-tempNum[j+1] != diff)
                {
                    flag = false;
                    break;
                }
            }
            
            if(flag == true)
            {
                ans++;
            }
        }
        
        cout << ans << endl;
    }
    
    return 0;
}