|
| 1 | +## 1. Hash Map |
| 2 | + |
| 3 | +::tabs-start |
| 4 | + |
| 5 | +```python |
| 6 | +class Solution: |
| 7 | + def mostVisitedPattern(self, username: List[str], timestamp: List[int], website: List[str]) -> List[str]: |
| 8 | + arr = list(zip(timestamp, username, website)) |
| 9 | + arr.sort() |
| 10 | + |
| 11 | + mp = defaultdict(list) |
| 12 | + for time, user, site in arr: |
| 13 | + mp[user].append(site) |
| 14 | + |
| 15 | + count = defaultdict(int) |
| 16 | + for user in mp: |
| 17 | + patterns = set() |
| 18 | + cur = mp[user] |
| 19 | + for i in range(len(cur)): |
| 20 | + for j in range(i + 1, len(cur)): |
| 21 | + for k in range(j + 1, len(cur)): |
| 22 | + patterns.add((cur[i], cur[j], cur[k])) |
| 23 | + for p in patterns: |
| 24 | + count[p] += 1 |
| 25 | + |
| 26 | + max_count = 0 |
| 27 | + res = tuple() |
| 28 | + for pattern in count: |
| 29 | + if count[pattern] > max_count or (count[pattern] == max_count and pattern < res): |
| 30 | + max_count = count[pattern] |
| 31 | + res = pattern |
| 32 | + |
| 33 | + return list(res) |
| 34 | +``` |
| 35 | + |
| 36 | +```java |
| 37 | +public class Solution { |
| 38 | + public List<String> mostVisitedPattern(String[] username, int[] timestamp, String[] website) { |
| 39 | + int n = timestamp.length; |
| 40 | + List<int[]> arr = new ArrayList<>(); |
| 41 | + for (int i = 0; i < n; i++) arr.add(new int[]{timestamp[i], i}); |
| 42 | + arr.sort((a, b) -> Integer.compare(a[0], b[0])); |
| 43 | + |
| 44 | + Map<String, List<String>> mp = new HashMap<>(); |
| 45 | + for (int[] p : arr) { |
| 46 | + int idx = p[1]; |
| 47 | + mp.computeIfAbsent(username[idx], k -> new ArrayList<>()).add(website[idx]); |
| 48 | + } |
| 49 | + |
| 50 | + Map<String, Integer> count = new HashMap<>(); |
| 51 | + for (String user : mp.keySet()) { |
| 52 | + List<String> cur = mp.get(user); |
| 53 | + Set<String> patterns = new HashSet<>(); |
| 54 | + for (int i = 0; i < cur.size(); i++) |
| 55 | + for (int j = i + 1; j < cur.size(); j++) |
| 56 | + for (int k = j + 1; k < cur.size(); k++) |
| 57 | + patterns.add(cur.get(i) + "#" + cur.get(j) + "#" + cur.get(k)); |
| 58 | + for (String p : patterns) |
| 59 | + count.put(p, count.getOrDefault(p, 0) + 1); |
| 60 | + } |
| 61 | + |
| 62 | + String res = ""; |
| 63 | + int max_count = 0; |
| 64 | + for (String p : count.keySet()) { |
| 65 | + int c = count.get(p); |
| 66 | + if (c > max_count || (c == max_count && p.compareTo(res) < 0)) { |
| 67 | + max_count = c; |
| 68 | + res = p; |
| 69 | + } |
| 70 | + } |
| 71 | + return Arrays.asList(res.split("#")); |
| 72 | + } |
| 73 | +} |
| 74 | +``` |
| 75 | + |
| 76 | +```cpp |
| 77 | +class Solution { |
| 78 | +public: |
| 79 | + vector<string> mostVisitedPattern(vector<string>& username, vector<int>& timestamp, vector<string>& website) { |
| 80 | + int n = timestamp.size(); |
| 81 | + vector<pair<int,int>> arr; |
| 82 | + for (int i = 0; i < n; ++i) arr.push_back({timestamp[i], i}); |
| 83 | + sort(arr.begin(), arr.end(), |
| 84 | + [](auto& a, auto& b){ return a.first < b.first; }); |
| 85 | + |
| 86 | + unordered_map<string, vector<string>> mp; |
| 87 | + for (auto& p : arr) mp[username[p.second]].push_back(website[p.second]); |
| 88 | + |
| 89 | + unordered_map<string,int> count; |
| 90 | + for (auto& kv : mp) { |
| 91 | + auto& cur = kv.second; |
| 92 | + unordered_set<string> patterns; |
| 93 | + for (int i = 0; i < (int)cur.size(); ++i) |
| 94 | + for (int j = i + 1; j < (int)cur.size(); ++j) |
| 95 | + for (int k = j + 1; k < (int)cur.size(); ++k) |
| 96 | + patterns.insert(cur[i] + "#" + cur[j] + "#" + cur[k]); |
| 97 | + for (auto& p : patterns) ++count[p]; |
| 98 | + } |
| 99 | + |
| 100 | + int maxCnt = 0; |
| 101 | + string res; |
| 102 | + for (auto& kv : count) |
| 103 | + if (kv.second > maxCnt || |
| 104 | + (kv.second == maxCnt && (res.empty() || kv.first < res))) { |
| 105 | + maxCnt = kv.second; |
| 106 | + res = kv.first; |
| 107 | + } |
| 108 | + |
| 109 | + vector<string> ans; |
| 110 | + string tmp; |
| 111 | + for (char ch : res) { |
| 112 | + if (ch == '#') { |
| 113 | + ans.push_back(tmp); |
| 114 | + tmp.clear(); |
| 115 | + } else { |
| 116 | + tmp += ch; |
| 117 | + } |
| 118 | + } |
| 119 | + ans.push_back(tmp); |
| 120 | + return ans; |
| 121 | + } |
| 122 | +}; |
| 123 | +``` |
| 124 | + |
| 125 | +```javascript |
| 126 | +class Solution { |
| 127 | + /** |
| 128 | + * @param {string[]} username |
| 129 | + * @param {number[]} timestamp |
| 130 | + * @param {string[]} website |
| 131 | + * @return {string[]} |
| 132 | + */ |
| 133 | + mostVisitedPattern(username, timestamp, website) { |
| 134 | + const n = timestamp.length; |
| 135 | + const arr = []; |
| 136 | + for (let i = 0; i < n; i++) arr.push([timestamp[i], i]); |
| 137 | + arr.sort((a, b) => a[0] - b[0]); |
| 138 | + |
| 139 | + const mp = new Map(); |
| 140 | + for (const [, idx] of arr) { |
| 141 | + const user = username[idx], site = website[idx]; |
| 142 | + if (!mp.has(user)) mp.set(user, []); |
| 143 | + mp.get(user).push(site); |
| 144 | + } |
| 145 | + |
| 146 | + const count = new Map(); |
| 147 | + for (const user of mp.keys()) { |
| 148 | + const cur = mp.get(user); |
| 149 | + const patterns = new Set(); |
| 150 | + for (let i = 0; i < cur.length; i++) { |
| 151 | + for (let j = i + 1; j < cur.length; j++) { |
| 152 | + for (let k = j + 1; k < cur.length; k++) { |
| 153 | + patterns.add(`${cur[i]}#${cur[j]}#${cur[k]}`); |
| 154 | + } |
| 155 | + } |
| 156 | + } |
| 157 | + for (const p of patterns) { |
| 158 | + count.set(p, (count.get(p) || 0) + 1); |
| 159 | + } |
| 160 | + } |
| 161 | + |
| 162 | + let maxCnt = 0, res = ""; |
| 163 | + for (const [pat, c] of count.entries()) { |
| 164 | + if (c > maxCnt || (c === maxCnt && (res === "" || pat < res))) { |
| 165 | + maxCnt = c; |
| 166 | + res = pat; |
| 167 | + } |
| 168 | + } |
| 169 | + return res.split("#"); |
| 170 | + } |
| 171 | +} |
| 172 | +``` |
| 173 | + |
| 174 | +```csharp |
| 175 | +public class Solution { |
| 176 | + public List<string> MostVisitedPattern(string[] username, int[] timestamp, string[] website) { |
| 177 | + int n = timestamp.Length; |
| 178 | + var arr = new List<(int t, int i)>(); |
| 179 | + for (int i = 0; i < n; i++) arr.Add((timestamp[i], i)); |
| 180 | + arr.Sort((a, b) => a.t.CompareTo(b.t)); |
| 181 | + |
| 182 | + var mp = new Dictionary<string, List<string>>(); |
| 183 | + foreach (var (t, idx) in arr) { |
| 184 | + string user = username[idx], site = website[idx]; |
| 185 | + if (!mp.ContainsKey(user)) mp[user] = new List<string>(); |
| 186 | + mp[user].Add(site); |
| 187 | + } |
| 188 | + |
| 189 | + var count = new Dictionary<string,int>(); |
| 190 | + foreach (var kv in mp) { |
| 191 | + var cur = kv.Value; |
| 192 | + var patterns = new HashSet<string>(); |
| 193 | + for (int i = 0; i < cur.Count; i++) |
| 194 | + for (int j = i + 1; j < cur.Count; j++) |
| 195 | + for (int k = j + 1; k < cur.Count; k++) |
| 196 | + patterns.Add($"{cur[i]}#{cur[j]}#{cur[k]}"); |
| 197 | + foreach (var p in patterns) { |
| 198 | + count[p] = count.ContainsKey(p) ? count[p] + 1 : 1; |
| 199 | + } |
| 200 | + } |
| 201 | + |
| 202 | + int maxCnt = 0; |
| 203 | + string res = ""; |
| 204 | + foreach (var kv in count) { |
| 205 | + if (kv.Value > maxCnt || |
| 206 | + (kv.Value == maxCnt && |
| 207 | + (res == "" || string.Compare(kv.Key, res, StringComparison.Ordinal) < 0))) { |
| 208 | + maxCnt = kv.Value; |
| 209 | + res = kv.Key; |
| 210 | + } |
| 211 | + } |
| 212 | + return new List<string>(res.Split('#')); |
| 213 | + } |
| 214 | +} |
| 215 | +``` |
| 216 | + |
| 217 | +::tabs-end |
| 218 | + |
| 219 | +### Time & Space Complexity |
| 220 | + |
| 221 | +* Time complexity: $O(n \log n + n * u + n ^ 3 * w)$ |
| 222 | +* Space complexity: $O(n * u + n ^ 3 * w)$ |
| 223 | + |
| 224 | +> Where $n$ is the size of the array $timestamp$, $u$ is the maximum length of any string in the array $username$, and $w$ is the maximum length of any string in the array $website$. |
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