save project

my_search.py

 import random
 import random
+# 使用二分查找法，找出9和20在列表里面的索引
 
 
-alist = []
+alist = [[1, 3, 5, 8, 11, 15, 17, 18, 20, 21]]
 for i in range(1, 101):
 for i in range(1, 101):
     alist.append(i)
     alist.append(i)
 num = random.choice(alist)
 num = random.choice(alist)
 # 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置
 # 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置
 
 
 def binary_search(alist,num):
 def binary_search(alist,num):
+    low=0
+    high=len(alist)-1
+    while (1):
+        mid=(low+high)//2
+        if alist[mid]==num:
+            print(mid)
+            break
+        elif alist[mid]<num:
+            low=mid+1
+        elif alist[mid]>num:
+            high=mid-1
+        if high<=low:
+            print("没")
+            break
+binary_search(alist,num)
\ No newline at end of file