save project

binary_search.py

+import random
+
+alist=[]
+for i in range(1,101):
+    alist.append(i)
+num=random.choice(alist)
 # 使用二分查找法，找出9和20在列表里面的索引
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
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+
+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
+
+result=binary_search(alist,num)
+print("数",num)
+print("索",result)
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