438.js

//Given two strings s and p, return an array of all the start indices of p's ana
//grams in s. You may return the answer in any order.
//
//
// Example 1:
//
//
//Input: s = "cbaebabacd", p = "abc"
//Output: [0,6]
//Explanation:
//The substring with start index = 0 is "cba", which is an anagram of "abc".
//The substring with start index = 6 is "bac", which is an anagram of "abc".
//
//
// Example 2:
//
//
//Input: s = "abab", p = "ab"
//Output: [0,1,2]
//Explanation:
//The substring with start index = 0 is "ab", which is an anagram of "ab".
//The substring with start index = 1 is "ba", which is an anagram of "ab".
//The substring with start index = 2 is "ab", which is an anagram of "ab".
//
//
//
// Constraints:
//
//
// 1 <= s.length, p.length <= 3 * 104
// s and p consist of lowercase English letters.
//
// Related Topics 哈希表
// 👍 514 👎 0


//leetcode submit region begin(Prohibit modification and deletion)
/**
 * @param {string} s
 * @param {string} p
 * @return {number[]}
 */
var findAnagrams = function (s, p) {
  const ret = [];
  const pc = Array.from(p).reduce((ar, c) => {
    ar[c.charCodeAt(0)] += 1;
    return ar;
  }, new Array(400).fill(0))

  let cur = pc.slice();
  let winFrom = 0;
  let winTo = 0;
  let count = p.length;
  while (true) {
    if (winTo == s.length) break;

    if (cur[s[winTo].charCodeAt(0)] > 0) {
      cur[s[winTo].charCodeAt(0)] -= 1;
      count -= 1;
      if (count == 0) {
        ret.push(winFrom);
        winFrom = winFrom + 1
        winTo = winFrom;
        cur = pc.slice();
        count = p.length;
      } else {
        winTo = winTo + 1;
      }
    } else {
      winFrom = winFrom + 1
      winTo = winFrom
      cur = pc.slice();
      count = p.length;
    }
  }

  return ret;
};
//leetcode submit region end(Prohibit modification and deletion)

const r = findAnagrams("cbaebabacd", "abc")
// const r = findAnagrams("abab", "ab")
console.log(`r: ` + JSON.stringify(r, null, 4) + '\n')