save project

my_search.py

 import random
 import random
 
 
 alist = []
 alist = []
-for i in range(1, 101):
+for i in range(1, 1000):
     alist.append(i)
     alist.append(i)
 num = random.choice(alist)
 num = random.choice(alist)
 # 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置
 # 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置
 
 
-def binary_search(alist,num):
+def binary_search(alist,n):
\ No newline at end of file
+    low = 0
+    high = len(alist)-1
+
+    while  high>=low:
+        mid = (low + high)//2
+        cai = alist[mid]
+        if cai == n:
+            return mid
+        elif cai < n:
+            low = mid + 1
+        else:
+            high = mid-1
+    return -10
+
+resulf = binary_search(alist,num)
+if resulf < 0:
+    print(str(num)+"没找到")
+else:
+    print(str(num)+"找到了，下标为"+str(resulf))
+num1=1000
+resulf = binary_search(alist,num1)
+if resulf < 0:
+    print(str(num1)+"没找到")
+else:
+    print(str(num1)+"找到了，下标为"+str(resulf))
\ No newline at end of file