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Code/README fixes for the "Palindrome Check".
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@ -102,7 +102,7 @@ a set of rules that precisely define a sequence of operations.
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* `A` [Combination Sum](src/algorithms/sets/combination-sum) - find all combinations that form specific sum
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* `A` [Combination Sum](src/algorithms/sets/combination-sum) - find all combinations that form specific sum
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* **Strings**
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* **Strings**
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* `B` [Hamming Distance](src/algorithms/string/hamming-distance) - number of positions at which the symbols are different
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* `B` [Hamming Distance](src/algorithms/string/hamming-distance) - number of positions at which the symbols are different
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* `B` [Palindrome Check](src/algorithms/string/palindrome-check) - is the string the same in reverse
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* `B` [Palindrome](src/algorithms/string/palindrome) - check if the string is the same in reverse
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* `A` [Levenshtein Distance](src/algorithms/string/levenshtein-distance) - minimum edit distance between two sequences
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* `A` [Levenshtein Distance](src/algorithms/string/levenshtein-distance) - minimum edit distance between two sequences
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* `A` [Knuth–Morris–Pratt Algorithm](src/algorithms/string/knuth-morris-pratt) (KMP Algorithm) - substring search (pattern matching)
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* `A` [Knuth–Morris–Pratt Algorithm](src/algorithms/string/knuth-morris-pratt) (KMP Algorithm) - substring search (pattern matching)
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* `A` [Z Algorithm](src/algorithms/string/z-algorithm) - substring search (pattern matching)
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* `A` [Z Algorithm](src/algorithms/string/z-algorithm) - substring search (pattern matching)
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@ -1,25 +0,0 @@
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# Palindrome Check
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A Palindrome is a string that reads the same forwards and backwards.
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This means that the second half of the string is the reverse of the
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first half.
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## Examples
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The following are palindromes (thus would return TRUE):
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- "a"
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- "pop" -> p + o + p
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- "deed" -> de + ed
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- "kayak" -> ka + y + ak
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- "racecar" -> rac + e + car
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The following are NOT palindromes (thus would return FALSE):
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- "rad"
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- "dodo"
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- "polo"
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## References
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[GeeksforGeeks - Check if a number is Palindrome](https://www.geeksforgeeks.org/check-if-a-number-is-palindrome/)
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@ -1,14 +0,0 @@
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import palindromeCheck from '../palindromeCheck';
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describe('palindromeCheck', () => {
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it('should return whether or not the string is a palindrome', () => {
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expect(palindromeCheck('a')).toBe(true);
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expect(palindromeCheck('pop')).toBe(true);
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expect(palindromeCheck('deed')).toBe(true);
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expect(palindromeCheck('kayak')).toBe(true);
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expect(palindromeCheck('racecar')).toBe(true);
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expect(palindromeCheck('rad')).toBe(false);
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expect(palindromeCheck('dodo')).toBe(false);
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expect(palindromeCheck('polo')).toBe(false);
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});
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});
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29
src/algorithms/string/palindrome/README.md
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29
src/algorithms/string/palindrome/README.md
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@ -0,0 +1,29 @@
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# Palindrome Check
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A [Palindrome](https://en.wikipedia.org/wiki/Palindrome) is a string that reads the same forwards and backwards.
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This means that the second half of the string is the reverse of the
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first half.
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## Examples
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The following are palindromes (thus would return `TRUE`):
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```
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- "a"
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- "pop" -> p + o + p
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- "deed" -> de + ed
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- "kayak" -> ka + y + ak
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- "racecar" -> rac + e + car
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```
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The following are NOT palindromes (thus would return `FALSE`):
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```
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- "rad"
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- "dodo"
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- "polo"
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```
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## References
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- [GeeksForGeeks - Check if a number is Palindrome](https://www.geeksforgeeks.org/check-if-a-number-is-palindrome/)
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@ -0,0 +1,15 @@
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import isPalindrome from '../isPalindrome';
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describe('palindromeCheck', () => {
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it('should return whether or not the string is a palindrome', () => {
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expect(isPalindrome('a')).toBe(true);
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expect(isPalindrome('pop')).toBe(true);
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expect(isPalindrome('deed')).toBe(true);
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expect(isPalindrome('kayak')).toBe(true);
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expect(isPalindrome('racecar')).toBe(true);
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expect(isPalindrome('rad')).toBe(false);
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expect(isPalindrome('dodo')).toBe(false);
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expect(isPalindrome('polo')).toBe(false);
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});
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});
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@ -3,9 +3,10 @@
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* @return {boolean}
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* @return {boolean}
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*/
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*/
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export default function palindromeCheck(string) {
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export default function isPalindrome(string) {
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let left = 0;
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let left = 0;
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let right = string.length - 1;
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let right = string.length - 1;
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while (left < right) {
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while (left < right) {
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if (string[left] !== string[right]) {
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if (string[left] !== string[right]) {
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return false;
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return false;
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@ -13,5 +14,6 @@ export default function palindromeCheck(string) {
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left += 1;
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left += 1;
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right -= 1;
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right -= 1;
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}
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}
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return true;
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return true;
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}
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}
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