save project

my_tree.py

-import turtle
-import random
-
-pen = turtle.Turtle()
-pen.color('sienna')
-# 画布大小
-w = turtle.Screen()
-w.bgcolor('wheat')      # wheat小麦
-
-# 移动到起点
-pen.left(90)
-pen.up()
-pen.backward(150)    # 后退
-pen.down()
-
-def tree(n):
-    if n>=0:
-        if n<=12:
-            color_list['snow','lightcoral']
-            color = random.choice(color_list)
-            pen.color(color)    
-            pen.pensize(n/3)
-        else:
-            pen.color('sienna')    
-            pen.pensize(n/10)
-        pen.forward(n)
-        angle = random.randint(0,30)
-        length = random.randint(1,15)
-        pen.right(angle)
-        tree(n-length)
-        pen.left(2*angle)
-        tree(n-length)
-        pen.right(angle)
-        pen.up()
-        pen.backward(n)
-        pen.down()
-
-tree(60)        
-turtle.done()
+num_list = [1,3,5,8,11,15,17,18,20,21]
+num = 8
+low = 0
+high = len(num_list)-1
+while low <= high:
+mid = (low + high)//2
+guess = num_list[mid]
+if mid == guess:
+    print("找到了")
+    break
+elif guess < num:
+    low = mid + 1
+else guess > num:
+    high = mid - 1
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