UVA1225 Digit Counting

Description

Trung is bored with his mathematics homeworks. He takes a piece of chalk and starts writing a sequence of consecutive integers starting with 1 to N(1 < N < 10000) . After that, he counts the number of times each digit (0 to 9) appears in the sequence. For example, with N = 13 , the sequence is:

12345678910111213

In this sequence, 0 appears once, 1 appears 6 times, 2 appears 2 times, 3 appears 3 times, and each digit from 4 to 9 appears once. After playing for a while, Trung gets bored again. He now wants to write a program to do this for him. Your task is to help him with writing this program.

Input 

The input file consists of several data sets. The first line of the input file contains the number of data sets which is a positive integer and is not bigger than 20. The following lines describe the data sets.

For each test case, there is one single line containing the number N .

Output 

For each test case, write sequentially in one line the number of digit 0, 1,...9 separated by a space.

Sample Input 

2 
3 
13

Sample Output 

0 1 1 1 0 0 0 0 0 0 
1 6 2 2 1 1 1 1 1 1

剛開始做這道題準備用數學方法，去找規律，但是覺得太麻煩，而且要考慮的情況太多，很容易出錯，就直接從1到n每個數遍歷過去了。

代碼如下：

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