文章目录
一、题目
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.
二、题解
cpp
class Solution {
public:
int countWords(vector<string>& words1, vector<string>& words2) {
unordered_map<string,int> map1;
unordered_map<string,int> map2;
for(auto w1:words1){
map1[w1]++;
}
for(auto w2:words2){
map2[w2]++;
}
int res = 0;
for(auto w1:words1){
if(map1[w1] == 1 && map2[w1] == 1) res++;
}
return res;
}
};