save project

my_search.py

@@ -6,4 +6,21 @@ 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 low<=high:
+        mid = (low+high)//2
+        guess = alist[mid]
+        if guess == num:
+            return mid
+        elif guess<num:
+            low = mid+1
+        else:
+            high = mid-1
+    return None
+SB = binary_search(alist,num)
+if SB == None:
+    print("没找到")
+else:
+    print("找到啦，他的值是："+str(alist[SB])+"，他的索引值是："+str(SB))