二分查找[最好 O(1) 平均O(logn) 最坏O(logn)]

#include <stdio.h>

int binSearch(int array[], int n, int key)
{
int low = 0, high = n - 1;
while(low <= high){
int middle = (low + high) / 2;
if(array[middle] == key)
return middle;
else
array[middle] > key ? high = middle - 1 : low = middle + 1;
}
return -1;
}

int binSearchRecurse(int array[], int low, int high, int key)
{
if(low <= high) {
int middle = (low + high) / 2;
if(array[middle] == key)
return middle;
else if(array[middle] > key)
return binSearchRecurse(array, low, middle - 1, key);
else
return binSearchRecurse(array, middle + 1, high, key);
}
return -1;
}

int main()
{
int a[] = {1,4,6,8,9,10};
//int result = binSearchRecurse(a, 0, 5, 6);
int result = binSearch(a, 6, 6);
printf("%d\n", result);
}