golang力扣leetcode 567.字符串的排列

package main
func checkInclusion(s1 string, s2 string) bool {
  wind := make(map[byte]int)
  need := make(map[byte]int)
  for i := range s1 {
    need[s1[i]]++
  }
  left, right, match := 0, 0, 0
  for right < len(s2) {
    c := s2[right]
    right++
    if need[c] != 0 {
      wind[c]++
      if wind[c] == need[c] {
        match++
      }
    }
    for right-left == len(s1) {
      if match == len(need) {
        return true
      }
      c = s2[left]
      left++
      if need[c] != 0 {
        if wind[c] == need[c] {
          match--
        }
        wind[c]--
      }
    }
  }
  return false
}