Add Length of Last Word C#

Author: hellomrsun

README.md

@@ -21,6 +21,7 @@ Solutions in various programming languages are provided. Enjoy it.
 12. [Combination Sum III](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/12-Combination-Sum-III)
 13. [Insert Interval](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/13-Insert-Interval)
 14. [House Robber](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/14-House-Robber)
+15. [Length of Last Word](https://github.com/AlgoStudyGroup/Leetcode/tree/master/September-LeetCoding-Challenge/15-Length-of-Last-Word)
 
 ## August LeetCoding Challenge
 Click [here](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/) for problem descriptions.

September-LeetCoding-Challenge/15-Length-of-Last-Word/Length-of-Last-Word.cs

@@ -0,0 +1,74 @@
+public class Solution {
+
+ //Solution 1
+ public class Solution {
+ public int LengthOfLastWord(string s) {
+ if(s.Length == 0) return 0;
+ 
+ var l = s.Split(' ').ToList();
+ var i = l.Count - 1;
+ while(i >= 0){
+ if(l[i] == ""){
+ i--;
+ }
+ else{
+ return l[i].Length;
+ }
+ }
+ 
+ return 0;
+ }
+}
+
+
+ //Solution 2
+ public int LengthOfLastWord(string s)
+ {
+ if (s.Length == 0) return 0;
+
+ int beginPosition = 0;
+ int endPosition = 0;
+ bool hasWord = false;
+ bool hasSpaceBeforeLastWord = false;
+
+ //Start by the end of string
+ for (int i = s.Length - 1; i >= 0; i--)
+ {
+ if (s[i] == ' ' && !hasWord)
+ {
+ //This condition improves performance
+ continue;
+ }
+ else if (s[i] != ' ' && !hasWord)
+ {
+ hasWord = true;
+ endPosition = i;
+ continue;
+ }
+ else if (s[i] == ' ' && hasWord)
+ {
+ beginPosition = i;
+ hasSpaceBeforeLastWord = true;
+ break;
+ }
+ }
+
+ //One word case
+ if (endPosition - beginPosition == 0 && hasWord)
+ return 1;
+
+ //No words case
+ if (endPosition - beginPosition == 0 && !hasWord)
+ return 0;
+
+ //Has word and has spaces before last words
+ if (endPosition - beginPosition != 0 && hasWord && hasSpaceBeforeLastWord)
+ return endPosition - beginPosition;
+
+ //Has word and has no space before last words
+ if (endPosition - beginPosition != 0 && hasWord && !hasSpaceBeforeLastWord)
+ return endPosition - beginPosition + 1;
+
+ return 0;
+ }
+}