Solution

Method 1 – Hash Map and Counting

Intuition

We use a hash map to track the set of unique minutes for each user. Then, for each user, we count how many users have each possible UAM (user active minutes) value.

Approach

For each log entry, add the minute to a set for the corresponding user ID.
For each user, count the size of their set (their UAM).
For each possible UAM value from 1 to k, count how many users have that UAM.
Return the answer array.

Code

[{"language":"C++","code":"class Solution {\npublic:\n    vector<int> findingUsersActiveMinutes(vector<vector<int>>& logs, int k) {\n        unordered_map<int, unordered_set<int>> mp;\n        for (auto& log : logs) mp[log[0]].insert(log[1]);\n        vector<int> ans(k);\n        for (auto& [id, st] : mp) {\n            int uam = st.size();\n            if (uam >= 1 && uam <= k) ans[uam-1]++;\n        }\n        return ans;\n    }\n};","lang":"cpp","html":"<pre class=\"shiki shiki-themes github-light github-dark\" style=\"background-color:#fff;--shiki-dark-bg:#24292e;color:#24292e;--shiki-dark:#e1e4e8\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">class</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\"> Solution</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> {</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">public:</span></span>\n<span class=\"line\"><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">    vector</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">&#x3C;</span><span style=\"color:#D73A49;--shiki-dark:#F97583\">int</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">> </span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">findingUsersActiveMinutes</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">(</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">vector</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">&#x3C;</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">vector</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">&#x3C;</span><span style=\"color:#D73A49;--shiki-dark:#F97583\">int</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">>>

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