auto save

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]
 num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-num = 20
+num = 2
 low = 0
 low = 0
 high = len(num_list)-1
 high = len(num_list)-1
 while True:
 while True:
-    mid = (low+high)//2
-    guess = num_list[mid]
-    if guess == num:
-        print("找到了",mid)
-        break
-    elif guess < num:
-        low = mid+1
+    if high >= low:
+        mid = (low+high)//2
+        guess = num_list[mid]
+        if guess == num:
+            print("找到了",mid)
+            break
+        elif guess < num:
+            low = mid+1
+        else:
+            high = mid - 1
     else:
     else:
-        high = mid - 1
+        print("没找到")
\ No newline at end of file
+        break
+        
\ No newline at end of file