Create : 58-Length-of-Last-Word

cpp/58-Length-of-Last-Word.cpp

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+class Solution {
+public:
+ /*
+ Approach: 
+ Traverse from end to the first whitespace character and count the number of letters.
+ Return the count as our pointer hits the whitespace character.
+ 
+ Time complexity: O(n)
+ Space complexity: O(1)
+ */ 
+ int lengthOfLastWord(string s) {
+ int n = s.length();
+
+ int ptr = n-1;
+ while(ptr >= 0 && s[ptr] == ' ') ptr--; /* Skip the trailing whitespaces */
+
+ int len = 0;
+ while(ptr >= 0 && s[ptr--] != ' ') len++; /* Counting the letters in the last word */
+ return len;
+ }
+};