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
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
\ No newline at end of file
+a = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+n=int(input('请输入你想查找的数字:'))
+start=0
+end=len(a)-1
+while True:
+    mid=(start+end)//2
+    if n > a[mid]:
+        start=mid+1
+    elif n==a[mid]:
+        print(n,'在',mid,'号位置')    
+        break
+    elif n<a[mid]:
+        end=mid-1
+    if start > end:
+        print(n,'不存在')
+        break