Navigating the Loop: Advanced Tips

This approach beautifully sidesteps non-alphabetical characters. But let's talk about the "how" for a moment. To ensure accuracy, remember to iterate the reversedAlpha array independently from the loop that scans the original string.

Optional: Simplifying with .shift()

If the thought of juggling another pointer or index leaves you dizzy, here's a simpler alternative: use the .shift() method. This function efficiently grabs the left-most element in an array, essentially doing the pointer's job for you. Imagine it as having a helper who hands you each reversed "gold coin" as you walk along your original path.

Method 2: The Two-Pointer Skip Technique

Method 2

Dual Pointers with a Twist

The second approach also involves using two pointers, much like our first method. However, this one comes with a twist: it skips over the non-alphabetical characters directly.

How to Skip Efficiently

Just like in a dance, when a couple realizes they are out of sync, they adjust their steps. Similarly, if either of the pointers encounters a non-alphabetical character, it simply "dances" past it, without making a swap.

By adopting this approach, you get to keep the original sequence of non-alphabetical characters intact while reversing only the alphabets. Think of it as flipping some tiles on a mosaic floor without disturbing the overall pattern.

1#include<iostream>
2#include<stdio.h>
3using namespace std;
4
5bool isAlpha(char c) {
6    return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
7}
8
9void swap(char arr[], int a, int b) {
10    char t = arr[a];
11    arr[a] = arr[b];
12    arr[b] = t;
13}
14
15string reverseOnlyAlphabetical(string str) {
16    int left = 0;
17    int right = str.size() - 1;
18
19    while (left < right) {
20        if (!isAlpha(str[left]))
21            left++;
22        else if (!isAlpha(str[right]))
23            right--;
24        else {
25            swap(&str[0], left++, right--);
26        }
27    }
28
29    return str;
30}
31
32int main() {
33    string str = "sea!$hells3";
34    cout << reverseOnlyAlphabetical(str);
35    return 0;
36}