save project

binary_search.py

 # 使用二分查找法，找出9和20在列表里面的索引
 # 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]
+import random
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+
+alist=[]
+for i in range(1,101):
+    alist.append(i)
+num=random.choice(alist)
+
+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('老师给的数是:',num) 
+print('找到了,它在列表里的索引是:',result)
+
+# bingo_num=20
+# num_list=[1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+# low=0
+# high=len(num_list)-1
+
+# while low<=high:
+#     mid=(low+high)//2
+#     guess_num=num_list[mid]
+#     if guess_num==bingo_num:
+#         print('找到了,它在列表里的索引是:',mid)
+#         break
+#     elif guess_num<bingo_num:
+#         low=mid+1
+#     elif guess_num>bingo_num:
+#         high=mid-1
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