Merge pull request #1541 from haseebzaki-07/new_branch_14

Check palindrome using deue

docs/Queue/check-palindrome-using-dequeue.md

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+---
+id: check-palindrome-using-deque
+title: "Check Palindrome Using Deque"
+sidebar_label: "Palindrome Check with Deque"
+sidebar_position: 9
+description: "A guide to checking if a string is a palindrome using a deque data structure for efficient operations."
+tags: [data structure, deque, palindrome]
+---
+
+# Check Palindrome Using Deque
+
+A palindrome is a string that reads the same forwards and backwards. This guide explains how to check if a string is a palindrome using a **deque** (double-ended queue) data structure, which allows for efficient operations at both ends.
+
+## Introduction
+
+Using a deque to check for palindromes leverages its ability to add or remove elements from both ends in constant time. This makes it a suitable choice for the task, as we can compare characters from the front and back of the string until we reach the center.
+
+![](https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTwWr4bJaQGsjcIJzTxYf_KG-rUl7g8lpQWlw&s)
+
+## Steps to Check Palindrome
+
+1. **Add** each character of the string to the deque.
+2. **Remove and compare** characters from both ends of the deque until the middle is reached.
+3. If all pairs match, the string is a palindrome; otherwise, it is not.
+
+## Implementation
+
+### Python Code
+
+```cpp
+
+#include <iostream>
+#include <deque>
+#include <string>
+using namespace std;
+
+bool isPalindrome(const string& s) {
+    deque<char> d;
+
+    // Load the deque with each character from the string
+    for (char ch : s) {
+        d.push_back(ch);
+    }
+
+    // Compare characters from both ends
+    while (d.size() > 1) {
+        if (d.front() != d.back()) {
+            return false;  // Not a palindrome if characters don't match
+        }
+        d.pop_front();  // Remove the front character
+        d.pop_back();   // Remove the back character
+    }
+
+    return true;  // All pairs matched, so it is a palindrome
+}
+
+int main() {
+    string str1 = "radar";
+    cout << str1 << " is a palindrome: " << (isPalindrome(str1) ? "True" : "False") << endl;
+
+    string str2 = "hello";
+    cout << str2 << " is a palindrome: " << (isPalindrome(str2) ? "True" : "False") << endl;
+
+    return 0;
+}
+```
+## Complexity
+### Time Complexity:
+is_palindrome: 
+𝑂(𝑛)
+O(n), where 𝑛 is the length of the string (since each character is dequeued once from both ends).
+### Space Complexity: 𝑂(𝑛)
+O(n), where 𝑛 is the number of characters in the deque.
+
+## Explanation of Code
+
+Initialize a deque with the characters of the string.
+Use a while loop to repeatedly remove characters from the front and back of the deque.
+Return False if any character pair doesn't match; otherwise, return True when the loop completes.
+
+## Applications
+The palindrome check has applications in string processing, data validation, and computer science algorithms. Deques provide an efficient way to check for palindromes with minimal memory overhead.