题目描述

The task is simple: given any positive integer N, you are supposed to count the total number of 1's in the decimal form of the integers from 1 to N. For example, given N being 12, there are five 1's in 1, 10, 11, and 12.

输入描述

Each input file contains one test case which gives the positive N (≤2​^30​​).

输出描述

For each test case, print the number of 1's in one line.

输入例子

12

输出例子

5

我的代码

#include<stdio.h>
int count=0;
void getAns(int a){
    int k;
    if(a<10 && a==1){
        count++;
    }
    if(a>=10){
        while(a>=10){
            k=a%10;
            a=a/10;
            if(k==1){
                count++;
            }
            if(a==1){
                count++;
            }
        }
    }
}

int main(){
    int n,sum=0;
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        getAns(i);
    }
    printf("%d",count);
    return 0;
}