000. Monchoka! Weekly Algos by your neighbourly scheme-r ;)

ianmuchina commented Feb 24, 2021

Solution in python

class Solution:
    def isPalindrome(self, x: int) -> bool:
        # reverse then compare
        initial = x

        rev = 0
        while x != 0:

            # Get the number in ones place
            #   eg: 123 % 10 = 3
            n = x % 10

            # Make space in rev
            rev = rev * 10
            # add n in the new space
            rev = rev + n

            # Delete the number in ones place
            #   eg: 123 / 10 = 12
            x =  math.trunc(x / 10)
            
        if initial == rev:
            return True
        else:
            return False

Reversing an integer mathematically

kodesoul commented Feb 24, 2021 •

edited

Solution in rust:

fn rev_int(num: i32) -> i32 {
    let mut num = num;
    let mut rev = 0;

    while num != 0  {
        rev *= 10;
        rev += num % 10;
        num /= 10;
    };
    rev
}

fn is_palindrome(n: i32) -> bool {
    n == rev_int(n)
}

Author

BonfaceKilz commented Feb 25, 2021 via email

Thanks for the submission! And it works. Here are a few (superficial) remarks from me:

Solution in python ```python

Would be nice if there was an "import math"...

class Solution:

No need for a class ey?

def isPalindrome(self, x: int) -> bool:

Normally in Python, I'd name functions in snake_case to stick to PEP8 ;)

# reverse then compare initial = x rev = 0

Trick for one liners like this is to have something like: ``` initial, rev = x, 0 ```

while x != 0: # Get the number in ones place # eg: 123 % 10 = 3 n = x % 10 # Make space in rev rev = rev * 10 # add n in the new space rev = rev + n

nitpick: rev *= 10 rev += n

# Delete the number in ones place # eg: 123 / 10 = 12 x = math.trunc(x / 10) if initial == rev: return True else: return False

For this, one return is good enough: ``` return initial == rev ```

…

-- Bonface M. K. D4F09EB110177E03C28E2FE1F5BBAE1E0392253F Humble GNU Emacs User / Bearer of scheme-y parens Curator: <https://upbookclub.com> / Twitter: @BonfaceKilz

Author

BonfaceKilz commented Feb 25, 2021 via email

fn rev_int(num: i32) -> i32 { let mut num = num; let mut rev = 0; while num != 0 { rev *= 10; rev += num % 10; num /= 10; }; rev } fn is_palindrome(n: i32) -> bool { n == rev_int(n) } ```

This looks succinct! :)

…

-- Bonface M. K. D4F09EB110177E03C28E2FE1F5BBAE1E0392253F Humble GNU Emacs User / Bearer of scheme-y parens Curator: <https://upbookclub.com> / Twitter: @BonfaceKilz

DMGithinji commented Mar 1, 2021 •

edited

`
function isPalindrome(x: number): boolean {
let rev = 0;
let copy = x;

    while(copy > 0) {
        const rem = copy%10;
        rev = rem + (rev * 10);
        copy = Math.floor(copy/10);
    }
    return rev === x;

}
`

Author

BonfaceKilz commented Mar 1, 2021 via email

DMG <notifications@github.com> writes:

` function isPalindrome(x: number): boolean { let rev = 0; let copy = x; let round = 0; while(copy > 0) { const rem = copy%10; rev = rem + (rev * 10); copy = Math.floor(copy/10); round++; } return rev === x; } `

Typescript(And succinct)! This works. Thanks for the submission \o/\o/

…

-- Bonface M. K. D4F09EB110177E03C28E2FE1F5BBAE1E0392253F Humble GNU Emacs User / Bearer of scheme-y parens Curator: <https://upbookclub.com> / Twitter: @BonfaceKilz

BonfaceKilz/00 Palindrome Numbers.md

Prelude

Last Week's Challenge

This Week's Challenge

ianmuchina commented Feb 24, 2021

kodesoul commented Feb 24, 2021 •

edited

BonfaceKilz commented Feb 25, 2021 via email

BonfaceKilz commented Feb 25, 2021 via email

DMGithinji commented Mar 1, 2021 •

edited

BonfaceKilz commented Mar 1, 2021 via email

BonfaceKilz/00 Palindrome Numbers.md

Prelude

Last Week's Challenge

This Week's Challenge

ianmuchina commented Feb 24, 2021

kodesoul commented Feb 24, 2021 • edited

BonfaceKilz commented Feb 25, 2021 via email

BonfaceKilz commented Feb 25, 2021 via email

DMGithinji commented Mar 1, 2021 • edited

BonfaceKilz commented Mar 1, 2021 via email

kodesoul commented Feb 24, 2021 •

edited

DMGithinji commented Mar 1, 2021 •

edited