2981. 找出出现至少三次的最长特殊子字符串 I

找出出现至少三次的最长特殊子字符串 I

• 难度: medium
• 原始链接: https://leetcode.cn/problems/find-longest-special-substring-that-occurs-thrice-i
• 标签: 哈希, 排序

解法一: 哈希, 排序

go

func maximumLength(s string) int {
  numList := make([][]int, 26)
  n := len(s)
  count := 0
  for i := 0; i < n; i++ {
    count++
    if i == n-1 || s[i] != s[i+1] {
      numList[s[i]-'a'] = append(numList[s[i]-'a'], count)
      count = 0
    }
  }
  ans := 0
  for _, list := range numList {
    if len(list) == 0 {
      continue
    }
    sort.Slice(list, func(i, j int) bool {
      return list[i] >= list[j]
    })
    list = append(list, 0, 0)
    ans = max(ans, max(list[0]-2, max(min(list[0]-1, list[1]), list[2])))
  }
  if ans == 0 {
    return -1
  }
  return ans
}