Codeforces 875A Classroom Watch 문제 해결

A. Classroom Watch time limit per test1 second memory limit per test512 megabytes inputstandard input outputstandard output Eighth-grader Vova is on duty today in the class. After classes, he went into the office to wash the board, and found on it the number n. He asked what is this number and the teacher of mathematics Inna Petrovna answered Vova that n is the answer to the arithmetic task for first-graders. In the textbook, a certain positive integer x was given. The task was to add x to the sum of the digits of the number x written in decimal numeral system.
Since the number n on the board was small, Vova quickly guessed which x could be in the textbook. Now he wants to get a program which will search for arbitrary values of the number n for all suitable values of x or determine that such x does not exist. Write such a program for Vova.
Input The first line contains integer n (1 ≤ n ≤ 109).
Output In the first line print one integer k — number of different values of x satisfying the condition.
In next k lines print these values in ascending order.
Examples input 21 output 1 15 input 20 output 0 Note In the first test case x = 15 there is only one variant: 15 + 1 + 5 = 21.
In the second test case there are no such x.
하나의 수 n을 주고 x에 x의 각 위치의 합이 n과 같은 숫자의 개수를 구하여 x를 출력한다.
가령 x가len의 자릿수라고 가정하면 x에 x의 각 자릿수와 n의 차이는 반드시len*9을 초과하지 않을 것이다. 폭력은 적당한 범위 내에서 한 번 훑어본다.

#include 

using namespace std;

int n;
vector <int> a;

bool check(int x) {
    int s = x;
    for(int i = 1; x; i++) s += x%10, x /= 10;
    if(s == n) return 1;
    return 0;
}

int main() {
    scanf("%d",&n);
    for(int i = (n-100 > 0) ? n-100 : 0; i <= n; i++) {
        if(check(i)) a.push_back(i);
    }
    printf("%d",a.size());
    for(int i = 0; i < a.size(); i++) printf("
%d",a[i]);
    return 0;
}