2085-CountCommonWordsWithOneOccurrence.go

package main

// 2085. Count Common Words With One Occurrence
// Given two string arrays words1 and words2, 
// return the number of strings that appear exactly once in each of the two arrays.

// Example 1:
// Input: words1 = ["leetcode","is","amazing","as","is"], words2 = ["amazing","leetcode","is"]
// Output: 2
// Explanation:
// - "leetcode" appears exactly once in each of the two arrays. We count this string.
// - "amazing" appears exactly once in each of the two arrays. We count this string.
// - "is" appears in each of the two arrays, but there are 2 occurrences of it in words1. We do not count this string.
// - "as" appears once in words1, but does not appear in words2. We do not count this string.
// Thus, there are 2 strings that appear exactly once in each of the two arrays.

// Example 2:
// Input: words1 = ["b","bb","bbb"], words2 = ["a","aa","aaa"]
// Output: 0
// Explanation: There are no strings that appear in each of the two arrays.

// Example 3:
// Input: words1 = ["a","ab"], words2 = ["a","a","a","ab"]
// Output: 1
// Explanation: The only string that appears exactly once in each of the two arrays is "ab".

// Constraints:
//     1 <= words1.length, words2.length <= 1000
//     1 <= words1[i].length, words2[j].length <= 30
//     words1[i] and words2[j] consists only of lowercase English letters.

import "fmt"

func countWords(words1 []string, words2 []string) int {
    res, mp1, mp2 := 0, make(map[string]int), make(map[string]int)
    for _, v := range words1 {
        mp1[v]++
    }
    for _, v := range words2 {
        mp2[v]++
    }
    for k, c := range mp1 {
        if c == 1 && mp2[k] == 1 { // 两个字符串数组中 都恰好出现一次
            res++
        }
    }
    return res
}

func main() {
    // Example 1:
    // Input: words1 = ["leetcode","is","amazing","as","is"], words2 = ["amazing","leetcode","is"]
    // Output: 2
    // Explanation:
    // - "leetcode" appears exactly once in each of the two arrays. We count this string.
    // - "amazing" appears exactly once in each of the two arrays. We count this string.
    // - "is" appears in each of the two arrays, but there are 2 occurrences of it in words1. We do not count this string.
    // - "as" appears once in words1, but does not appear in words2. We do not count this string.
    // Thus, there are 2 strings that appear exactly once in each of the two arrays.
    fmt.Println(countWords([]string{"leetcode","is","amazing","as","is"}, []string{"amazing","leetcode","is"})) // 2
    // Example 2:
    // Input: words1 = ["b","bb","bbb"], words2 = ["a","aa","aaa"]
    // Output: 0
    // Explanation: There are no strings that appear in each of the two arrays.
    fmt.Println(countWords([]string{"b","bb","bbb"}, []string{"a","aa","aaa"})) // 0
    // Example 3:
    // Input: words1 = ["a","ab"], words2 = ["a","a","a","ab"]
    // Output: 1
    // Explanation: The only string that appears exactly once in each of the two arrays is "ab".
    fmt.Println(countWords([]string{"a","ab"}, []string{"a","a","a","ab"})) // 1
}