2+22+222+2222+22222（此时n=5）

C语言解答

#include<stdio.h>

int main()
{
	int a,n,i;
	int j;
	long int sn=0;
	scanf("%d %d",&a,&n);
	for(i=0;i<n;i++)
	{
		j=a%10;
		sn=sn+a;
		a=j+a*10;
	}
	printf("%ld\n",sn);
	return 0;
}

C++解答

#include <stdio.h>
#include <math.h>
int main() {
	int n, a, s, i, ans;
	scanf("%d %d", &a, &n);
	s = 0; ans = 0;
	for (i = 1;i <= n;i++) {
		s = s * 10 + a;
		ans = ans + s;
	}
	printf("%d\n", ans);
	return 0;
}

Java解答

import java.util.*;
public class Main {
    public static void main(String args[]) {
        Scanner cin = new Scanner(System.in);
        int m,n;
        m = cin.nextInt();
        n = cin.nextInt();
        double sum=0;
        for(int i=0;i<n;i++){
            for(int j=n-i;j>0;j--){
                sum+=Math.pow(10, i)*m;
            }
        }
        System.out.printf("%.0f\n", sum);
    }
}

Python解答

a,n = raw_input().split()
x = 0
for i in xrange(1,int(n)+1):
  x = x + int(a*i)
print x