一. 二分查找

二. 代碼實現一：使用遞歸

def binary_search(alist, item):"""二分查找：使用遞歸"""n = len(alist)if n > 0:mid = n // 2if alist[mid] == item:return Trueelif item < alist[mid]:return binary_search(alist[:mid],item)else:return binary_search(alist[mid+1:],item)return Falseif __name__ == '__main__':li = [17,20,26,31,44,54,55,77,93]print(binary_search(li,55))print(binary_search(li,100))

三. 代碼實現二：非遞歸

def binary_search_2(alist,item):"""二分查找：非遞歸"""n = len(alist)first = 0last = n-1while first <= last:mid = (first + last)//2if alist[mid] == item:return Trueelif item < alist[mid]:last = mid-1else:first = mid + 1return Falseif __name__ == '__main__':li = [17,20,26,31,44,54,55,77,93]print(binary_search_2(li,55))print(binary_search_2(li,100))