查找之折半查找

#include<stdio.h>
#define N 10

void QuickSort(int a[],int left, int right);
int BinSearch(int a[], int low, int high, int key);
int main()
{
    int a[N] = {2,8,4,9,7,6,5,3,1,0};
    int j = 0, i;
    QuickSort(a, 0, sizeof(a)/sizeof(a[0])-1);
    i = BinSearch(a, 0, N-1, 6);
    printf("%d
", i);
    for(j = 0; j < N; j++){
        printf("%d ",a[j]);
    }
    printf("
");
    return 0;
}
//折半查找
int BinSearch(int a[], int low, int high, int key){
    while(low <= high){
        int mid = (low + high) / 2;
        if(a[mid] < key)
            low = mid + 1;
        else if(a[mid] > key)
            high = mid - 1;
        else
            return mid;  //查找成功
    } 
    
    return -1; //查找失败
}

void QuickSort(int a[],int left, int right){
    int key = a[left];
    int i = left;
    int j = right;
    if(left >= right){
        return;
    }
    while(i < j){
        while(i<j && a[j] >= key){
            j--;
        }
        a[i] = a[j];
        while(i<j && a[i] <= key){
            i++;
        }
        a[j] = a[i];
    
    }
    
    a[i] = key;
    QuickSort(a, left, i-1);
    QuickSort(a, i+1, right);
}