Implemented suggesting improvements
This commit is contained in:
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### anagrams
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⚠️ **WARNING**: This function's execution time increases exponentially with each character. Anything more than 8 to 10 characters will cause your browser to hang as it tries to solve all the different combinations.
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Generates all anagrams of a string (contains duplicates).
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Use recursion.
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For each letter in the given string, create all the partial anagrams for the rest of its letters.
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Use `Array.map()` to combine the letter with each partial anagram, then `Array.reduce()` to combine all anagrams in one array.
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Base cases are for string `length` equal to `2` or `1`.
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```js
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const anagrams = str => {
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if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str];
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return str
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.split('')
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.reduce(
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(acc, letter, i) =>
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acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)),
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[]
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);
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};
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```
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```js
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anagrams('abc'); // ['abc','acb','bac','bca','cab','cba']
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```
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16
snippets/isAnagram.md
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16
snippets/isAnagram.md
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### isAnagram
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Checks if a string is an anagram of another string (case-insensitive, ignores spaces, punctuation and special characters).
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Use `String.toLowerCase()`, `String.replace()` with an appropriate regular expression to remove unnecessary characters, `String.split('')`, `Array.sort()` and `Array.join('')` on both strings to normalize them, then check if their normalized forms are equal.
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```js
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const isAnagram = (str1, str2) => {
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const normalize = str => str.toLowerCase().replace(/[^a-z0-9]/gi, '').split('').sort().join('');
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return normalize(str1) === normalize(str2);
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}
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```
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```js
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isAnagram('iceman', 'cinema'); // true
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```
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30
snippets/permutations.md
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30
snippets/permutations.md
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### permutations
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⚠️ **WARNING**: This function's execution time increases exponentially with each array element. Anything more than 8 to 10 entries will cause your browser to hang as it tries to solve all the different combinations.
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Generates all permutations of an array's elements (contains duplicates).
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Use recursion.
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For each element in the given array, create all the partial permutations for the rest of its elements.
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Use `Array.map()` to combine the element with each partial permutation, then `Array.reduce()` to combine all permutations in one array.
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Base cases are for array `length` equal to `2` or `1`.
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```js
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const permutations = arr => {
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if (arr.length <= 2) return arr.length === 2 ? [arr, [arr[1], arr[0]]] : arr;
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return arr.reduce(
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(acc, item, i) =>
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acc.concat(
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permutations([...arr.slice(0, i), ...arr.slice(i + 1)]).map(val => [
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item,
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...val,
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])
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),
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[]
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);
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};
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```
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```js
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permutations([1, 33, 5]) // [ [ 1, 33, 5 ], [ 1, 5, 33 ], [ 33, 1, 5 ], [ 33, 5, 1 ], [ 5, 1, 33 ], [ 5, 33, 1 ] ]
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```
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@ -1,37 +0,0 @@
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### permuteAll
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Uses recursion and `Array.push()` to return all the permutations of the given input in an array.
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```js
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const permuteAll = (input) => {
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const result = [];
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let inputState = input;
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if (typeof input === 'string') inputState = input.split('');
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if (typeof input === 'number') inputState = (input).toString().split('');
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const permute = (arr, m = []) => {
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(arr.length === 0)
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? result.push(m)
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: arr.forEach((_, i) => {
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let curr = arr.slice();
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let next = curr.splice(i, 1);
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permute(curr.slice(), m.concat(next));
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});
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};
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permute(inputState);
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return (typeof input === 'string')
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? result.map(variant => variant.join(''))
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: (typeof input === 'number')
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? result.map(variant => parseFloat(variant.join('')))
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: result;
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};
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```
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```js
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permuteAll('sun') // [ 'sun', 'snu', 'usn', 'uns', 'nsu', 'nus' ]
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permuteAll([1, 33, 5]) // [ [ 1, 33, 5 ], [ 1, 5, 33 ], [ 33, 1, 5 ], [ 33, 5, 1 ], [ 5, 1, 33 ], [ 5, 33, 1 ] ]
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permuteAll(345) // [ 345, 354, 435, 453, 534, 543 ]
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```
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27
snippets/stringPermutations.md
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27
snippets/stringPermutations.md
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### stringPermutations
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⚠️ **WARNING**: This function's execution time increases exponentially with each character. Anything more than 8 to 10 characters will cause your browser to hang as it tries to solve all the different combinations.
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Generates all permutations of a string (contains duplicates).
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Use recursion.
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For each letter in the given string, create all the partial permutations for the rest of its letters.
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Use `Array.map()` to combine the letter with each partial permutation, then `Array.reduce()` to combine all permutations in one array.
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Base cases are for string `length` equal to `2` or `1`.
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```js
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const stringPermutations = str => {
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if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str];
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return str
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.split('')
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.reduce(
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(acc, letter, i) =>
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acc.concat(stringPermutations(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)),
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[]
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);
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};
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```
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```js
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stringPermutations('abc'); // ['abc','acb','bac','bca','cab','cba']
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```
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