Implement lengthOfLastWord function in Solution class

[aryaman0406]

PR Title Format: 58.Length of Last Word.cpp💡 IntuitionThe most straightforward way to find the length of the last word is to iterate through the string backward from the end. This allows us to skip any trailing spaces immediately and then count the characters of the first non-space sequence we encounter.✍️ ApproachThe solution uses a two-stage backward iteration approach:Skip Trailing Spaces: Start the index i at the end of the string ($\text{s.length() - 1}$). Use a while loop to decrement i as long as the character $\text{s[i]}$ is a space (' ') and $\text{i}$ is within the string bounds. This ensures we stop at the last character of the actual last word or at the beginning of the string.Count Word Characters: Initialize a counter $\text{length}$ to $0$. Use a second while loop, again decrementing $\text{i}$, but this time, stop when $\text{s[i]}$ is a space or $\text{i}$ goes below $0$. In this loop, simply increment $\text{length}$ for every non-space character encountered.Return: The final value of $\text{length}$ is the length of the last word. This approach avoids creating any new strings or using built-in string splitting functions, making it efficient with $O(N)$ time complexity and $O(1)$ space complexity.Code Solution (C++)C++class Solution {
public:
int lengthOfLastWord(string s) {
int length = 0;
// Start from the end of the string
int i = s.length() - 1;

    // 1. Skip all trailing spaces
    while (i >= 0 && s[i] == ' ') {
        i--;
    }

    // 2. Count the length of the last word
    while (i >= 0 && s[i] != ' ') {
        length++;
        i--;
    }

    return length;
}

};
🔗 Related IssuesBy submitting this PR, I confirm that:[x] This is my original work not totally AI generated[x] I have tested the solution thoroughly on leetcode[x] I have maintained proper PR description format[x] This is a meaningful contribution, not spam

Summary by Sourcery

New Features:

• Implement lengthOfLastWord method to scan a string backward, skip trailing spaces, and count the last word’s length in O(N) time and O(1) space.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Adds a C++ implementation of lengthOfLastWord in the Solution class by performing a two-pass backward traversal to skip trailing spaces and then count the last word’s characters, achieving O(N) time and O(1) space without extra allocations.

File-Level Changes

Change	Details	Files
Implement backward traversal to compute last word length	Initialize index at string’s end First loop skips trailing spaces Second loop counts non-space characters Return the accumulated length	58.Length of Last Word.cpp

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