python二分法实现实例

def BinarySearch(array,t):
low = 0
height = len(array)-1
while low < height:
mid = (low+height)/2
if array[mid] < t:
low = mid + 1

elif array[mid] > t:
height = mid - 1

else:
return array[mid]

return -1

if __name__ == "__main__":
print BinarySearch([1,2,3,34,56,57,78,87],57)

结果：57

3.时间复杂度:O(log2n);

注意：二分查找的前提必须待查找的序列有序。