public static void main(String[] args) {

String[][] d = { { "doc1", "t1", "t2", "t3" }, { "doc2", "t0", "t2", "t3" }, { "doc3", "t1", "t6", "t7" },

{ "doc4", "t1", "t2", "t4" }, { "doc5", "t6", "t100", "t8" } };

String[] t = { "t1", "t2", "t3", "t" };

solution(d, t);

}

static List<doc> list = new ArrayList<>();

static HashSet<String> tagsh = new HashSet<>();

public static String[] solution(String[][] dataSource, String[] tags) {

HashMap<String, Integer> hm = new HashMap<>();

// -- 1. doc마다 tag개수 세어주기

// -- 개선

// tags를 hashset에 넣어주고, doc의 태그드를 확인

// 내가 구현한 find : O(n)

// 개선한다면,O(1)

for (String tag : tags) {

tagsh.add(tag);

}

// ----

int docTaglen = dataSource[0].length;

for (int i = 0; i < dataSource.length; i++) {

String docName = dataSource[i][0];

for (int t = 0; t < tags.length; t++) {

String tag = tags[t];

// 태그이름이 있다면 cnt+1

for (int j = 1; j < docTaglen; j++) {

if (tag.equals(dataSource[i][j])) {

int idx = find(docName);

if (find(docName) == -1) {

list.add(new doc(docName, 1));

} else {

int cnt = list.get(idx).cnt;

list.get(idx).addCnt();

}

}

}

}

}

Comparator<doc> Comp = new Comparator<doc>() {

public int compare(doc a, doc b) {

if (a.cnt == b.cnt)

return a.name.compareTo(b.name);

else

return b.cnt - a.cnt;

}

};

list.sort(Comp);

int maxLen = list.size() > 10 ? 10 : list.size();

String[] answer = new String[maxLen];

for (int i = 0; i < maxLen; i++) {

answer[i] = list.get(i).name;

System.out.println(list.get(i).name + " " + list.get(i).cnt);

}

return answer;

}

private static int find(String docName) {

for (int i = 0; i < list.size(); i++) {

if (list.get(i).name.equals(docName)) {

return i;

}

}

return -1;

}

private static boolean find2(String docName) {

if (tagsh.contains(docName))

return true;

return false;

}

String name;

int cnt;

doc(String name, int cnt) {

this.name = name;

this.cnt = cnt;

}

void addCnt() {

this.cnt++;

}

}