UVA - 1225 Digit Counting

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

首先枚举所有，因为都是小于10000。
开始是都没有想清楚是怎么做，当后来看到原来是1~N的全部数的个数才明白怎么做

#include <iostream>

using namespace std;

int ans[10005][10];

void count_Digit(){
for(int i = 1; i < 10001;i++){
int k = i;
for(int k = i; k ; k/=10) ans[i][k%10]++;
for(int j = 0; j <= 9; j++)ans[i][j] += ans[i-1][j];
}
}

int main(){
int T;
count_Digit();
while(cin>>T){
while(T--){
int d;
cin>>d;
for(int i = 0;i<9;i++){
cout<<ans[d][i]<<" ";
}
cout<<ans[d][9]<<endl;
}
}
return 0;
}