[class2] (백준 2231) 분해합

#include <stdio.h>
#include <math.h>
int main()
{
    int input,place;
    int n = 1;
    int result = -1;
    
    scanf("%d",&input);
    place = 1000000;
    while(1)
    {
        if(input/place != 0)
            break;
        place/=10;
    }
    
    while(1)
    {
        if(place/10==0)
            break;
        place/=10;
        n++;
    }
    int checknum;
    int temp;
    for(int i = input - 9*n;i<input + 9*n;i++)
    {
        checknum = i;
        for(int j = n;j>0;j--)
        {
            temp=i/pow(10,j-1);
            checknum+=temp%10;
        }
        if(checknum==input)
        {
            result=i;
            break;
        }
    }
    
    if(result==-1)
        printf("0\n");
    else
        printf("%d\n",result);
    return 0;
}

 

 

 

 

#include <iostream>
using namespace std;
int main()
{
    int N,sum,temp;
    cin >> N;
    
    
    for(int i = N-54 ; i<N ; i++)
    {
        sum = i;
        temp = i;
        do
        {
            sum+=temp%10;
            temp/=10;
        } while(temp != 0);
        
        if(sum == N)
        {
            cout << i <<endl;
            return 0;
        }
    }
    cout << 0 <<endl;
    return 0;
}