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]
 num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
+start=0
+end=len(num_list)-1
+mid=(start+end)//2
+guss=int(input("请输入你要查找的数字："))
+
+
+while True:
+    if guss == num_list[mid]:
+        print(guss,"的位置在",mid)
+        break
+    if guss < num_list[mid]:
+        end=mid-1
+    if guss > num_list[mid]:
+        start=mid+1        
+    if start>end:
+        print(guss,"不存在")
+        break
+    mid=(start+end)//2