uva_1583_Digit Generator

For a positive integer N , the digit-sum of N is defined as the sum of N itself and its digits. When M is the digitsum of N , we call N a generator of M .

For example, the digit-sum of 245 is 256 (= 245 + 2 + 4 + 5). Therefore, 245 is a generator of 256.

Not surprisingly, some numbers do not have any generators and some numbers have more than one generator. For example, the generators of 216 are 198 and 207.

You are to write a program to find the smallest generator of the given integer.

input

Your program is to read from standard input. The input consists of T test cases. The number of test cases Tis given in the first line of the input. Each test case takes one line containing an integer N , 1

N

100, 000 .

output

Your program is to write to standard output. Print exactly one line for each test case. The line is to contain a generator of N for each test case. If N has multiple generators, print the smallest. If N does not have any generators, print 0.

The following shows sample input and output for three test cases.

Sample input

3 
216 
121 
2005
      

Sample output

198 
0 
1979      

思路：      

一开始想输入一个数从1开始算一个数，超时了；看了书后，看到打表，然后自己写了一个，从1开始算每一个数的生成元，结果跑的时间太长了；在看书上的代码之后，尼玛倒着来的。      

代码：      

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int a[100005];
void gen()
{
    int i,x,y;
    memset(a,0,sizeof(a));
    for(i=1;i<100005;i++)
    {
        x=i;
        y=i;
        while(x) {y+=x%10;x/=10;}
        if(a[y]==0||i<a[y])
            a[y]=i;
    }
}
int main()
{
    int m,n;
    scanf("%d",&m);
    gen();
    while(m--)
    {
        scanf("%d",&n);
        printf("%d\n",a[n]);
    }
    return 0;
}