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my_search.py

@@ -6,4 +6,18 @@ 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):
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+    low_kun = 0
+    high_kun = len(alist)-1
+    while high_kun >= low_kun:
+        mid_kun = (low_kun+high_kun)//2
+        if alist[mid_kun] == num:
+            return mid_kun
+        elif alist[mid_kun] < num:
+            low_kun = mid_kun + 1
+        else:
+            high_kun = mid_kun - 1
+    return None
+result = binary_search(alist,num)
+print("随机数是",num)
+print("索引是",result)
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