fix: Some Ruby code (#1231)

* fix: ruby code block - chapter computational complexity

* fix: ruby code - chapter array and linkedlist

codes/ruby/chapter_array_and_linkedlist/array.rb

@@ -45,8 +45,8 @@ end
 ### 删除索引 index 处的元素 ###
 def remove(nums, index)
   # 把索引 index 之后的所有元素向前移动一位
-  for i in index...nums.length
-    nums[i] = nums[i + 1] || 0
+  for i in index...(nums.length - 1)
+    nums[i] = nums[i + 1]
   end
 end
 

docs/chapter_computational_complexity/time_complexity.md

@@ -195,7 +195,7 @@
         a = a + 1   # 1 ns
         a = a * 2   # 10 ns
         # 循环 n 次
-        (n...0).each do # 1 ns
+        (0...n).each do # 1 ns
             puts 0      # 5 ns
         end
     end