We are given some website visits: the user with name username[i]
visited the website website[i]
at time timestamp[i]
.
A 3-sequence is a list of websites of length 3 sorted in ascending order by the time of their visits. (The websites in a 3-sequence are not necessarily distinct.)
Find the 3-sequence visited by the largest number of users. If there is more than one solution, return the lexicographically smallest such 3-sequence.
Example 1:
Input: username = ["joe","joe","joe","james","james","james","james","mary","mary","mary"], timestamp = [1,2,3,4,5,6,7,8,9,10], website = ["home","about","career","home","cart","maps","home","home","about","career"]
Output: ["home","about","career"]
Explanation:
The tuples in this example are:
["joe", 1, "home"]
["joe", 2, "about"]
["joe", 3, "career"]
["james", 4, "home"]
["james", 5, "cart"]
["james", 6, "maps"]
["james", 7, "home"]
["mary", 8, "home"]
["mary", 9, "about"]
["mary", 10, "career"]
The 3-sequence ("home", "about", "career") was visited at least once by 2 users.
The 3-sequence ("home", "cart", "maps") was visited at least once by 1 user.
The 3-sequence ("home", "cart", "home") was visited at least once by 1 user.
The 3-sequence ("home", "maps", "home") was visited at least once by 1 user.
The 3-sequence ("cart", "maps", "home") was visited at least once by 1 user.
Note:
3 <= N = username.length = timestamp.length = website.length <= 50
1 <= username[i].length <= 10
0 <= timestamp[i] <= 10^9
1 <= website[i].length <= 10
- Both
username[i]
andwebsite[i]
contain only lowercase characters. - It is guaranteed that there is at least one user who visited at least 3 websites.
- No user visits two websites at the same time.
class Solution { public List<String> mostVisitedPattern(String[] username, int[] timestamp, String[] website) { Map<String, List<Pair>> map = new HashMap<>(); int len = username.length; for (int i = 0; i < len; i++) { if (map.get(username[i]) == null) { map.put(username[i], new ArrayList<>()); } map.get(username[i]).add(new Pair(timestamp[i], website[i])); } Map<String, Integer> count = new HashMap<>(); String res = ""; for (String str: map.keySet()) { List<Pair> list = map.get(str); // avoid the same user visit 3-seq Set<String> set = new HashSet<>(); Collections.sort(list, (a, b) -> a.time - b.time); for (int i = 0; i < list.size(); i++) { for (int j = i + 1; j < list.size(); j++) { for (int k = j + 1; k < list.size(); k++) { String cur = list.get(i).web + " " + list.get(j).web + " " + list.get(k).web; if (!set.contains(cur)) { count.put(cur, count.getOrDefault(cur, 0) + 1); set.add(cur); } if (res.equals("") || count.get(cur) > count.get(res) || count.get(cur) == count.get(res) && cur.compareTo(res) < 0) { res = cur; } } } } } String[] strArr = res.split(" "); List<String> resList = new ArrayList<>(); for (String str: strArr) { resList.add(str); } return resList; } } class Pair { String web; int time; public Pair(Integer time, String web) { this.web = web; this.time = time; } }