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
 # 使用二分查找法，找出9和20在列表里面的索引
-num=9
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-low=0
-nigh=len(num_list)-1
-while high>=low:
-     mid=(low+high)//2
-     guess_num=num_list[mid]
-     if guess_num==num:
-        print("找到了,它在列表中的位置是:",mid)
-        break
-    elif guess_num < num:
-        low=mid+1
-    elif guess_num>num:
-        high=mid-1    
+import random
+alist=[]
+for i in range(1,100):
+    alist.append(i)
+num=random.choice(alist)  
+
+def binary_search(alist,num):
+    low=0
+    high=len(alist)-1
+    while high>=low:
+        mid=(low+high)//2
+        guess_num=alist[mid]
+        if guess_num==num:
+            return mid
\ No newline at end of file
+        elif guess_num < num:
+            low=mid+1
+        elif guess_num>num:
+            high=mid-1  
+    return None
+result=binary_search(alist,num) 
+print("随机数为",num)
+print("它在列表中的索引",result)
+
+