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Author: assassint2017

Sort Characters By Frequency/Sort_Characters_By_Frequency.cpp

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+// Runtime: 16 ms, faster than 74.99% of C++ online submissions for Sort Characters By Frequency.
+// Memory Usage: 10.6 MB, less than 82.35% of C++ online submissions for Sort Characters By Frequency.
+
+struct cell
+{
+    cell () : chr('x'), times(0) {}
+    cell (char c, int t) : chr(c), times(t) {}
+    char chr;
+    int times;
+};
+
+class Solution 
+{
+public:
+    string frequencySort(string s) 
+    {
+        vector<cell> hashmap(128);
+        for (int i = 0; i < 128; ++i)
+            hashmap[i].chr = i;
+            
+        for (char chr : s)
+            ++hashmap[chr].times;
+        
+        auto comp = [](const cell& item1, const cell& item2){return item1.times > item2.times;};
+        sort(hashmap.begin(), hashmap.end(), comp);
+        
+        string res = "";
+        for (auto item : hashmap)
+            for (int i = 0; i < item.times; ++i)
+                res += item.chr;
+        
+        return res;
+    }
+};