Solution as on 20-03-2022 08:22 am

Author: knockcat

0895. Maximum Frequency Stack.cpp

@@ -0,0 +1,55 @@
+// 895.✅ Maximum Frequency Stack
+
+class FreqStack
+{
+public:
+    // freqMap is to map element to its frequency
+    map<int, int> freqMap;
+
+    // set map is to map frequency to the
+    // element list with this frequency
+    map<int, stack<int>> setMap;
+
+    // for keeping record of maximum frequency
+    int maxfreq = 0;
+
+    FreqStack()
+    {
+        // KNOCKCAT
+    }
+
+    // insert
+    void push(int val)
+    {
+        // frequency of x
+        int freq = freqMap[val] + 1;
+
+        // Mapping of x with its frequency
+        freqMap[val] = freq;
+
+        // if freq is greater than maxfreq
+        // update max freq
+        if (freq > maxfreq)
+            maxfreq = freq;
+
+        // Mapping element to  its frequency list
+        setMap[freq].push(val);
+    }
+
+    // remove
+    int pop()
+    {
+        // remove element from setMap
+        // from maximum frequency list
+        int top = setMap[maxfreq].top();
+        setMap[maxfreq].pop();
+
+        // decrement the frequcy of the popped element
+        --freqMap[top];
+
+        // if whole list popped decrement the max freq
+        if (setMap[maxfreq].size() == 0)
+            --maxfreq;
+        return top;
+    }
+};