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
 num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
 
-num = 9
-low = 0
-high = len(num_list)-1
-while low < high:
-    mid = (low + high)//2
-    guess = num_list[mid]
-    if guess == num:
-        print('找到了，它在列表里的索引是' + mid) 
-    elif guess < num:
-        low = mid + 1
-    else:
-        high = mid + 1
-if low > high:
-    print("没找到")
\ No newline at end of file
+def brinary_search(alist,num):
+    low = 0
+    high = len(alist)-1
+    while low <= high:
+        mid = (low + high)//2
+        guess = alist[mid]
+        if guess == num: 
+            return mid
+        elif guess < num:
+            low = mid + 1
+        else:
+            high = mid - 1
+    if low > high:
+ 
+brinary_search(num_list,20)
\ No newline at end of file