save project

my_search.py

@@ -6,4 +6,21 @@ for i in range(1, 101):
 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):
\ No newline at end of file
+
+    low = 0
+    high = len(alist)-1
+    while low <= high: 
+        mid = (low+high)//2
+        guess_num = alist[mid]
+        if guess_num == num:
+            print("找到了，他在列表里是:",mid)
+            break
+        elif guess_num < num:
+            low  = mid + 1
+        elif guess_num > num:
+            high= mid-1   
+    return None
+result = binary_search(alist,num)
+print("老师给的数是:",num)
+print("他在列表里的索引是:",result)
\ No newline at end of file