# 实现一个二分查找 # 输入:一个顺序list # 输出: 待查找的元素的位置 def binarySearch(alist, item): first = 0 last = len(alist) - 1 while first <= last: mid = (first + last)//2 print(mid) if alist[mid] > item: last = mid - 1 elif alist[mid] < item: first = mid + 1 else: return mid+1 return -1 test = [0, 1, 2, 8, 13, 17, 19, 32, 42] print(binarySearch(test, 3))