save project

my_search.py

 import random
 import random
-
-alist = []
-for i in range(1, 101):
+alist=[]
+for i in range(1,101):
     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
-
-def binary_search(alist,num):
+def binary_search (alist,num):
+    low = 0
+    high=len(alist)-1
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+    while low<=high:
+        mid=(low+high)//2
+        g=alist[mid]
+        if g == num:
+            return mid
+        elif g<num:
+            low=mid+1
+        elif g>num:
+            high=mid-1
+    return None
+result=binary_search(alist,num)
+print('数是:',num)
+print('索引:',result)
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