top-k-freq-elems solutions

Author: dylan-jung

top-k-frequent-elements/dylan-jung.cpp

@@ -0,0 +1,23 @@
+class Solution {
+public:
+    vector<int> topKFrequent(vector<int>& nums, int k) {
+        unordered_map<int, int> m;
+        map<int, vector<int>> freq;
+        for(auto i: nums) m[i] += 1;
+        for(auto item: m) {
+            auto [k, v] = item;
+            freq[v].push_back(k);
+        }
+
+        vector<int> ans;
+        ans.reserve(k);
+        auto it = freq.rbegin();
+        while(k > 0) {
+            auto kth = it->second;
+            ans.insert(ans.end(), kth.begin(), kth.end());
+            k-=kth.size();
+            it++;
+        }
+        return ans;
+    }
+};