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Author: kerong2002

C++/1636. Sort Array by Increasing Frequency.cpp

@@ -0,0 +1,31 @@
+class Solution {
+public:
+    vector<int> frequencySort(vector<int>& nums) {
+        map<int, int> mp;
+        for (auto num : nums) {
+            mp[num]++;
+        }
+
+        vector<pair<int, int>> freq;
+        for (auto x : mp) {
+            freq.push_back(x);
+        }
+        // for (auto x : mp) {
+        //     cout << x.first << "," << x.second << "\n";
+        // }
+        sort(freq.begin(), freq.end(), [](const pair<int, int>& a, const pair<int, int>& b) {
+            if (a.second == b.second) {
+                return a.first > b.first;
+            }
+            return a.second < b.second;
+        });
+
+        vector<int> ans;
+        for (auto y : freq) {
+            for (int x = 0 ; x < y.second; ++x) {
+                ans.push_back(y.first);
+            }
+        }
+        return ans;
+    }
+};