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# Program to print all palindromes in a given range

Given a range of numbers, print all palindromes in the given range. For example if the given range is {10, 115}, then output should be {11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111}
We can run a loop from min to max and check every number for palindrome. If the number is a palindrome, we can simply print it.

Implementation:

## C++

 `#include``using` `namespace` `std;` `// A function to check if n is palindrome``int` `isPalindrome(``int` `n)``{``    ``// Find reverse of n``    ``int` `rev = 0;``    ``for` `(``int` `i = n; i > 0; i /= 10)``        ``rev = rev*10 + i%10;` `    ``// If n and rev are same, then n is palindrome``    ``return` `(n==rev);``}` `// prints palindrome between min and max``void` `countPal(``int` `min, ``int` `max)``{``    ``for` `(``int` `i = min; i <= max; i++)``        ``if` `(isPalindrome(i))``          ``cout << i << ``" "``;``}` `// Driver program to test above function``int` `main()``{``    ``countPal(100, 2000);``    ``return` `0;``}`

## Java

 `// Java Program to print all``// palindromes in a given range` `class` `GFG``{``    ` `    ``// A function to check``    ``// if n is palindrome``    ``static` `int` `isPalindrome(``int` `n)``    ``{``        ` `        ``// Find reverse of n``        ``int` `rev = ``0``;``        ``for` `(``int` `i = n; i > ``0``; i /= ``10``)``            ``rev = rev * ``10` `+ i % ``10``;``            ` `        ``// If n and rev are same,``        ``// then n is palindrome``        ``return``(n == rev) ? ``1` `: ``0``;``    ``}``    ` `    ``// prints palindrome between``    ``// min and max``    ``static` `void` `countPal(``int` `min, ``int` `max)``    ``{``        ``for` `(``int` `i = min; i <= max; i++)``            ``if` `(isPalindrome(i)==``1``)``                ``System.out.print(i + ``" "``);``    ``}``    ` `    ``// Driver Code``    ``public` `static` `void` `main(String args[])``    ``{``        ``countPal(``100``, ``2000``);``    ``}``}` `// This code is contributed by Taritra Saha.`

## Python3

 `# Python3 implementation of above idea` `# A function to check if n is palindrome``def` `isPalindrome(n: ``int``) ``-``> ``bool``:` `    ``# Find reverse of n``    ``rev ``=` `0``    ``i ``=` `n``    ``while` `i > ``0``:``        ``rev ``=` `rev ``*` `10` `+` `i ``%` `10``        ``i ``/``/``=` `10` `    ``# If n and rev are same,``    ``# then n is palindrome``    ``return` `(n ``=``=` `rev)` `# prints palindrome between min and max``def` `countPal(minn: ``int``, maxx: ``int``) ``-``> ``None``:``    ``for` `i ``in` `range``(minn, maxx ``+` `1``):``        ``if` `isPalindrome(i):``            ``print``(i, end ``=` `" "``)` `# Driver Code``if` `__name__ ``=``=` `"__main__"``:``    ``countPal(``100``, ``2000``)` `# This code is contributed by``# sanjeev2552`

## C#

 `// C# Program to print all``// palindromes in a given range``using` `System;` `class` `GFG``{` `// A function to check``// if n is palindrome``public` `static` `int` `isPalindrome(``int` `n)``{` `    ``// Find reverse of n``    ``int` `rev = 0;``    ``for` `(``int` `i = n; i > 0; i /= 10)``    ``{``        ``rev = rev * 10 + i % 10;``    ``}` `    ``// If n and rev are same,``    ``// then n is palindrome``    ``return` `(n == rev) ? 1 : 0;``}` `// prints palindrome between``// min and max``public` `static` `void` `countPal(``int` `min,``                            ``int` `max)``{``    ``for` `(``int` `i = min; i <= max; i++)``    ``{``        ``if` `(isPalindrome(i) == 1)``        ``{``            ``Console.Write(i + ``" "``);``        ``}``    ``}``}` `// Driver Code``public` `static` `void` `Main(``string``[] args)``{``    ``countPal(100, 2000);``}``}` `// This code is contributed by Shrikant13`

## Javascript

 ``

Output

```101 111 121 131 141 151 161 171 181 191 202 212 222 232 242
252 262 272 282 292 303 313 323 333 343 353 363 373 383 393 404
414 424 434 444 454 464 474 484 494 505 515 525 535 545 555 565
575 585 595 606 616 626 636 646 656 666 676 686 696 707 717 727
737 747 757 767 777 787 797 808 818 828 838 848 858 868 878 888
898 909 919 929 939 949 959 969 979 989 999 1001 1111 1221 1331
1441 1551 1661 1771 1881 1991 ```

Time Complexity:

Time complexity of function to check if a number N is palindrome or not is O(logN).

We are calling this function each time while iterating from min to max.

So the time complexity will be O(Dlog(M)).

Where,

D= max-min

M = max

Auxiliary Space: O(1)

#### Approach#2: Using filter

This approach defines a function is_palindrome that checks if a given number is a palindrome. It then defines a function palindrome_range that takes a range of numbers and returns a list of all palindromic numbers in that range using a combination of the range, filter, and list functions.

#### Algorithm

1. Define a function that takes two integer arguments as the range of numbers to check for palindromes.
2. Create a list of all integers in the range.
3. Use map and lambda to filter the list to only include palindromes.
4. Return the list of palindromes.

## Python3

 `def` `is_palindrome(num):``    ``return` `str``(num) ``=``=` `str``(num)[::``-``1``]` `def` `palindrome_range(start, end):``    ``nums ``=` `list``(``range``(start, end``+``1``))``    ``palindromes ``=` `list``(``filter``(``lambda` `x: is_palindrome(x), nums))``    ``return` `palindromes` `start``=``100``end``=``2000``print``(palindrome_range(start, end))`

## Javascript

 `// This function checks whether a given number is a palindrome or not``function` `is_palindrome(num) {``    ``return` `String(num) === String(num).split(``""``).reverse().join(``""``);``}` `// This function returns a list of all palindrome numbers within a given range``function` `palindrome_range(start, end) {``    ``let nums = Array.from({length: (end - start) + 1}, (_, i) => i + start);``    ``let palindromes = nums.filter(num => is_palindrome(num));``    ``return` `palindromes;``}` `// Example usage``let start = 100;``let end = 2000;``console.log(palindrome_range(start, end));`

Output

`[101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494, 505, 515, 525, 535, 545, 555, 565, 575, 585, 595, 606, 616, 626, 636, 646, 656, 666, 676, 686, 696, 707, 717, 727, 737, 747, 757, 767, 777, 787, 797, 808, 818, 828, 838, 848, 858, 868, 878, 888, 898, 909, 919, 929, 939, 949, 959, 969, 979, 989, 999, 1001, 1111, 1221, 1331, 1441, 1551, 1661, 1771, 1881, 1991]`

Time complexity: O(n*k), where n is the number of integers in the range and k is the length of the largest integer in the range.

Auxiliary Space: O(m), where m is the number of palindromes in the range

My Personal Notes arrow_drop_up