leetcode1002-查找共用字符

题目描述

• 给定字符串数组 words，找出所有的共用字符（包括重复字符）
• 任意顺序返回

示例

输入：words = ["bella","label","roller"]
输出：["e","l","l"]

输入：words = ["cool","lock","cook"]
输出：["c","o"]

题解

• 虽然是简单题，但是是简单题里需要绕一下的
• 思路
  1. 数据范围只有 100，暴力模拟也能过
  2. 用一个数组当字母的哈希表；遍历字符串，维护字符频率的最小值；根据词频生成答案

func commonChars(words []string) []string {
    minFreq := [26]int{}
    for i := range minFreq { minFreq[i] = 200 }

    for _, word := range words {
        freq := [26]int{}
        for _, w := range word { freq[w - 'a'] ++ }
        for i, f := range freq[:] {
            if f < minFreq[i] {
                minFreq[i] = f
            }
        }
    }
    
    res := []string{}
    for i := byte(0); i < 26; i ++ {
        for j := 0; j < minFreq[i]; j ++ {
            res = append(res, string('a' + i))
        }
    }
    return res
}