Problem A:Delete Number

Time Limit:1000MS  Memory Limit:65536K
Total Submit:820 Accepted:149

Description

Given 2 integer number n and m. You can delete m digits from the number n, then number n changes to a new number n1. Tell me how to delete the number, you can get the smallest one.
For example,


 m: 1        n: 1456

 n1 may be 145, 156, 146, 456

 the smallest one is 145. Then n1 should be 145.

Input

The input consists of T test cases. The number of them (T) is given on the first line of the input file. Each test case consists of one single line containing two integer number m(1 <= m <= 1000), and n(1 <= n < 101000).

Output

Your program must output a single line for each test case. The line should contain the number n1.

Sample Input


1
1 1456
Sample Output


145
Hint

if the number is 000345 you should output 345

代码：

#include<stdio.h>
main()
{
    int t,m,i,j,f,c,s;
    long str[10],k;
    char n;
    while(scanf("%d",&t)!=EOF)
    {
        for(i=1;i<=t;i++)
        {
            for(j=0;j<=9;j++)
            {
                str[j]=0;
            }
            scanf("%d",&m);
            getchar();
            while(scanf("%c",&n))
            {
                if(n=='\n')
                {
                    break;
                }
                else
                {
                    s=n-'0';
                    str[s]++;
                }
            }
            c=1;
            for(j=9;j>=0;j--)
            {
                for(;c<=m;c++)
                {
                    if(str[j]==0)
                    break;
                    str[j]=str[j]-1;
                }
            }
            for(j=1;j<=9;j++)
            {
                for(k=1;k<=str[j];k++)
                {
                    printf("%d",j);
                }
            }
            printf("\n");
        }
    }
}

看不懂E文。。。