[2018 카카오 공채] 뉴스 클러스터링

Solution.java

import java.util.LinkedList;
import java.util.List;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

// https://programmers.co.kr/learn/courses/30/lessons/17677

class Solution {
    public int solution(String str1, String str2) {
        List<String> s1 = split2(str1);
        List<String> s2 = split2(str2);

        int n1 = intersectCount(s1, s2);
        int n2 = unionCount(s1, s2);
        if (n1 == 0 && n2 == 0) return 65536;

        return n1 * 65536 / n2;
    }

    public List<String> split2(String str) {
        return IntStream.range(0, str.length() - 1)
                .mapToObj(i -> str.substring(i, i + 2))
                .map(String::toUpperCase)
                .filter(s -> Pattern.matches("[A-Z]+", s))
                .collect(Collectors.toList());
    }

    public int intersectCount(List<String> s1, List<String> s2) {
        List<String> ss2 = new LinkedList<>(s2);

        int count = 0;
        for (String s : s1) {
            if (ss2.remove(s)) count += 1;
        }
        return count;
    }

    public int unionCount(List<String> s1, List<String> s2) {
        List<String> ss2 = new LinkedList<>(s2);

        int count = 0;
        for (String s : s1) {
            ss2.remove(s);
            count += 1;
        }
        return count + ss2.size();
    }
}