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
 # 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]
-mid = (low+high)//2
-guess = num_list[mid]
-if guess == num:
-    print("找到了")
-    break
-elif guess < num:
-    low = mid-1
-else:
-    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
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+        guess = alist[mid]
+        if guess == num:
+            return mid
+        elif guess < num:
+            low = mid+1
+        else:
+            high = mid-1
+    return None
+resuit = binary_search(alist,num)
+print("老师给的数是",num)
+print("它在列表里的索引是",resuit)
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