save project

my_search.py

@@ -6,4 +6,22 @@ for i in range(1, 101):
 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
 
-def binary_search(alist,num):
\ No newline at end of file
+def binary_search(alist,num):
+    low=0
+    high=len(alist)-1
+    
+    while True:
+        mid=(low+high)//2
+        if high>=low:
+            if alist[mid]==num:
+                print(str(num)+"在列表中的索引为"+str(mid))
+                break
+            if alist[mid]>num:
+                high=mid-1
+            if alist[mid]<num:
+                low=mid+1
+        if high<low:
+            print("None")
+            break
+
+binary_search(alist,254)
\ No newline at end of file