无序数组中用 快速排序的分治思想 寻找第k大元素

#include <stdio.h>

int *ga;
int galen;
void print_a(){
    for(int i = ; i < galen; i++){
        printf("%d ",ga[i]);
    }
    printf("\n");
}

//k = di k da yuan su
int quick_findk(int *a, int len, int k){
    if(len <= )
        return a[];
    int *p,*l,*r,tmp;
    p=&a[len-];
    l=a;
    r=&a[len-];
    while(l < p){
        printf("len:%d , k:%d\n",len,k);
        print_a();
        while(*l<*p && l!=p)
            l++;
        while(*r>*p && r>l)
            r--;

        if(l != r && l < r){
            tmp = *l;
            (*l) = (*r);
            *r = tmp;
        }else{
            tmp = *p;
            (*p) = (*l);
            *l = tmp;
            print_a();
            int index = l - a;
            printf("index:%d v:%d\n",index,a[index]);
            if(index == len-k){
                return *l;
            }else if(index < len-k){//in right
                return quick_findk(&a[index+],len-index-,k);
            }else if(index > len-k){//in left
                return quick_findk(a,index,k-(len - index));
            }
        }
    }
}

void main(){
    int a[] = {,,,,,};
    int len = sizeof(a) / sizeof(a[]);
    ga = a;
    galen = len;
    int r = quick_findk(a, len, ); //
    printf("%d \n",r);
}

root@ubuntu:~/cdir# gcc quicksort_findk.c -o quicksort_findk.bin -g
root@ubuntu:~/cdir# ./quicksort_findk.bin
len: , k:

len: , k:

index: v:
len: , k:

index: v:
len: , k:

index: v:
len: , k:

index: v:
 

最后 = 3