The kth great number

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65768/65768 K (Java/Others)

Problem Description
Xiao Ming and Xiao Bao are playing a simple Numbers game. In a round Xiao Ming can choose to write down a number, or ask Xiao Bao what the kth great number is. Because the number written by Xiao Ming is too much, Xiao Bao is feeling giddy. Now, try to help Xiao Bao.
 

Input
There are several test cases. For each test case, the first line of input contains two positive integer n, k. Then n lines follow. If Xiao Ming choose to write down a number, there will be an " I" followed by a number that Xiao Ming will write down. If Xiao Ming choose to ask Xiao Bao, there will be a "Q", then you need to output the kth great number.
 

Output
The output consists of one integer representing the largest number of islands that all lie on one line.
 

Sample Input
8 3
I 1
I 2
I 3
Q
I 5
Q
I 4
Q
 

Sample Output
1
2
3

Hint
Xiao  Ming  won't  ask  Xiao  Bao  the  kth  great  number  when  the  number  of  the  written number is smaller than k. (1=<k<=n<=1000000).

你是怎么的思路？？

我做出来了，给你们代码吧
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
const int maxn=1000002;
int num[maxn];
int n,k;
int cmp(const void *x,const void *y)
{
    return *(int*)y-*(int*)x;
}
void wp(int p,int q)
{
    int i;
    for(i=k-1;i>=p;i--)
    {
        num[i+1]=num[i];
    }
    num[p]=q;
}
int main()
{
    int i,j,s,f,q;
    char str;
    while(scanf("%d%d",&n,&k)!=EOF)
    {
        j=0;
        getchar();
        memset(num,0,sizeof(num));
        while((str=getchar())!=EOF)
        {
            if(str=='I')
            {
                scanf("%d",&q);
                num[j]=q;
                j++;
            }
            else
            {
                qsort(num,j,sizeof(num[0]),cmp);
                s=num[k-1];
                printf("%d\n",s);
                getchar();
                break;
            }
            getchar();
        }
        for(i=j+1;i<n;i++)
        {
            str=getchar();
            if(str=='I')
            {
                scanf("%d",&q);
                if(q>s)
                {
                    if(q>=num[0])
                    {
                        wp(0,q);
                    }
                    else
                    {
                        for(f=k-1;f>0;f--)
                        {
                            if(q>num[f]&&q<=num[f-1])
                            {
                                wp(f,q);
                            }
                        }
                    }
                    s=num[k-1];
                }
            }
            else
            printf("%d\n",s);
            getchar();
        }
    }
    return 0;
}