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algorithm: palindrome number #93

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algorithm: palindrome number #93

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1650f6e
Is Palindrome Number
fatima-0000 Jan 23, 2023
1e32b19
Is Palindrome Number update
fatima-0000 Jan 23, 2023
ce03e0f
Added tests and updated Directory.md
fatima-0000 Jan 23, 2023
f790f54
updated Directory.md
fatima-0000 Jan 23, 2023
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1 change: 1 addition & 0 deletions DIRECTORY.md
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
* [Is Even](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_even.ts)
* [Is Leap Year](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_leap_year.ts)
* [Is Odd](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_odd.ts)
* [Is Palindrome](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/is_palindrome.ts)
* [Lowest Common Multiple](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/lowest_common_multiple.ts)
* [Perfect Square](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/perfect_square.ts)
* [Pronic Number](https://github.com/TheAlgorithms/TypeScript/blob/HEAD/maths/pronic_number.ts)
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18 changes: 18 additions & 0 deletions maths/is_palindrome.ts
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@@ -0,0 +1,18 @@
/**
* A function to see if a number is a Pallindrome
* @param number The input integer
* @return {boolean} True or False based on the integer
* @example isPalindrome(12321) => true | isPalindrome(455) => false
* @see https://en.wikipedia.org/wiki/Palindromic_number
* @author FatimaChariwala <https://github.com/fatima-0000>
*/

export const IsPalindrome = (number: number): boolean => {
let reverseString = "";
let stringValue = number.toString();
let length = stringValue.length - 1;
for (let i = length; i >= 0; --i) {
reverseString = reverseString + stringValue[i];

@appgurueu appgurueu Jan 24, 2023

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Why build a reverse string using repeated string concatenations when you could instead just check character-wise equality right in this loop?

}
return stringValue == reverseString;
};
10 changes: 10 additions & 0 deletions maths/test/is_palindrome.test.ts
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import { IsPalindrome } from "../is_palindrome";

describe("IsPalindrome", () => {
test.each([[5, true], [1234, false], [12321, true], [32.23, true], [31343, false]])(
"correct output for for %i",

@appgurueu appgurueu Jan 24, 2023

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double "for"

(nums, expected) => {
expect(IsPalindrome(nums)).toBe(expected);
},
);
});