438.js

/** ------------------------------------------------------------------------------
 * 
 * 2023-02-05
 * 438. Find All Anagrams in a String
 * https://leetcode.com/problems/find-all-anagrams-in-a-string/
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {string} s
 * @param {string} p
 * @return {number[]}
 */
var findAnagrams = function (s, p) {
  if (p.length > s.length) return [];
  const output = [];

  const map = new Map();

  for (let i = 0; i < p.length; i++) {
    const character = p[i];
    if (map.has(character)) {
      map.set(character, map.get(character) + 1);
    } else {
      map.set(character, 1);
    }
  }

  for (let i = 0; i <= s.length - p.length; i++) {
    if (output[output.length - 1] === i - 1 && s[i - 1] === s[i + p.length - 1]) {
      output.push(i);
      continue;
    }
    const newMap = new Map(map);
    for (let j = i + p.length - 1; j >= i; j--) {
      const character = s[j];
      if (!newMap.has(character)) {
        i = j;
        break;
      } else if (newMap.get(character) !== 1) {
        newMap.set(character, newMap.get(character) - 1);
      } else {
        newMap.delete(character);
      }
    }
    if (!newMap.size) {
      output.push(i);
    }
  }

  return output;
};

console.log(findAnagrams("cbaebabacd", "abc"));