save project

my_search.py

@@ -4,6 +4,17 @@ for i in range(1, 101):
     alist.append(i)
     alist.append(i)
 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):
-    low=0
+    low=0           #最低索引
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+    high=len(num)-1        #最高索引
+    while low<=high:            #最低索引小于等于最高索引
+        mid=(low+high)//2
+        guess=alist[mid]
+        if guess==num:
+            return mid
+        elif guess<num:
+            low=mid+1
+        else:
+            high=mid-1
+r=binary_search(alist,5)
+print(r)
\ No newline at end of file