index.ts

// HELP:

export function findAnagrams(s: string, p: string) {
  let len = p.length
  let hash: any = {}
  let ans: any = {}
  let res = []

  for (let i = 0, l = p.length; i < l; i++) {
    let index = p.charCodeAt(i) - 97
    ans[index] = ~~ans[index] + 1
  }

  for (let i = 0, l = s.length; i < l; i++) {
    let index = s.charCodeAt(i) - 97
    hash[index] = ~~hash[index] + 1

    if (i >= len) {
      let index = s.charCodeAt(i - len) - 97
      hash[index] = ~~hash[index] - 1
    }
    if (i + 1 >= len) {
      help() && res.push(i - len + 1)
    }
  }

  function help() {
    for (let i = 0; i < 26; i++) {
      if (~~hash[i] !== ~~ans[i]) return false
    }

    return true
  }

  return res
}