auto save

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]
+# 使用二分查找法，找出数字在列表里面的索引
+num_list = [1,3,5,8,11,15,17,18,20]
 low = 0
 low = 0
 high = len(num_list)-1
 high = len(num_list)-1
 
 
 while True:
 while True:
-    mid = (low+high)//2
-    guess = num_list[mid]
-    if guess == 20:
-        print('找到这个数了！')
-        print(str(mid))
+    print('输入Q退出程序！')
+    number = input('请输入要寻找的数：')
+    if number == Q:
         break
         break
-    elif guess < 20:
-        low = mid+1
-    else:
-        high = mid-1
-    if high <= low:
-        print('没有这个数！')
+    elif number != int:
         break
         break
-low = 0
-high = len(num_list)-1
-while True:
+    else:
+        while True:
             mid = (low+high)//2
             mid = (low+high)//2
             guess = num_list[mid]
             guess = num_list[mid]
-    if guess == 9:
+            if guess == int(number):
                 print('找到这个数了！')
                 print('找到这个数了！')
-        print(str(mid))
+                print('这个数在列表中的索引为'+str(mid))
                 break
                 break
-    elif guess < 9:
+            elif guess < int(number):
                 low = mid+1
                 low = mid+1
             else:
             else:
                 high = mid-1
                 high = mid-1
             if high <= low:
             if high <= low:
-        print('没有这个数！')
+                print('列表中没有这个数！')
                 break
                 break