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
-bingo_num=20
-num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-low = 0
-high =len(num_list)-1
- 
-while low <= high:
-    mid = (low+high) // 2
-    guess_num = num_list[mid]
-    if guess_num==bingo_num:
-        print("找到了，是",mid)
-        break
-    if guess_num<bingo_num:
-        low=mid+1
-    if guess_num>bingo_num:
-        high=mid-1
+import random
+alist = []
+for i in range(1,101):
+    alist.append(i)
+num = random.choice(alist)
+
+def binary_search(alist,num):
+    low = 0
+    high =len(alist)-1
+    while low <= high:
+        mid = (low+high) // 2
+        guess_num = alist[mid]
+        if guess_num==num:
+            return mid
+        if guess_num<num:
+            low=mid+1
+        if guess_num>num:
+            high=mid-1
+    return None
+result = binary_search(alist,num)
+print("给的",num)
+print("索引",result)