save project

binary_search.py

-# 使用二分查找法，找出9和20在列表里面的索引
-bingo_num=20
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-list=0
-low=0
-high=len(num_list)-1
-while low<=high:
+import random    
+alist=[]       
+for i in range(1,101):
+    alist.append(i)
+    num=random.choice(alist)
+
+def binary_search(alist,num):
+    low=0
+    high=len(alist)-1
+    while low<=high:
         mid=(low+high)//2
         mid=(low+high)//2
-    guess_num=num_list[mid]
-    if guess_num==bingo_num:
-        print("找到了，它在列表里的索引是：",mid)
-        break
-    elif guess_num<bingo_num:
+        guess=alist[mid]
+        if guess==num:
+            return mid
+        elif guess<num:
             low=mid+1
             low=mid+1
-    elif guess_num>bingo_num:
-        high=mid    
-       
-
-
-
-
-
+        else:
+            high=mid-1     
+    return None
+a=binary_search(alist,20)
+print(a)