백준 1065번 C++

#include <iostream>

#include <math.h>

using namespace std;

int findnum(int x) {

int num = x;

int ans = 100, count = 99;

while (ans <= num) {

int hundred = ans / 100;

int ten = ans % 100 / 10;

int one = ans % 100 % 10;

if ((ten * 2) == (hundred + one))

count++;

ans++;

}

return count;

}

int main(void) {

int num;

cin >> num;

if (num >= 100)

num = findnum(num);

cout << num;

}