Create: 0058-length-of-last-word.rb (neetcode-gh#2018)

* Create 0058-length-of-last-word.rb

Two solutions:
- Simple one line solution
- Double pointer solution

* Update 0058-length-of-last-word.rb

Strip not needed in the one liner!

* Don't need to pass blank string arg to split

Even more simpler!

ruby/0058-length-of-last-word.rb

@@ -0,0 +1,22 @@
+# @param {String} s
+# @return {Integer}
+
+#simple one liner
+def length_of_last_word(s)
+  s.split.last.length
+end
+
+#double pointer
+def length_of_last_word(s)
+    left = -1
+    while s[left] == ' ' do
+        left -= 1
+    end
+
+    right = left
+    while s[left] && s[left] != ' ' do
+        left -=1
+    end
+
+    right - left
+end