Create 1172.Dinner-Plate-Stacks.cpp

Design/1172.Dinner-Plate-Stacks/1172.Dinner-Plate-Stacks.cpp

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+class DinnerPlates {
+    unordered_map<int, vector<int>>Plate;
+    int leftNotFull;
+    int rightNotEmpty;
+    int cap;
+
+public:
+    DinnerPlates(int capacity) {
+        leftNotFull = 0;
+        rightNotEmpty = -1;
+        cap = capacity; 
+    }
+
+    void push(int val) {
+        Plate[leftNotFull].push_back(val);
+        while (Plate[leftNotFull].size()==cap)
+            leftNotFull++;
+
+        rightNotEmpty = max(rightNotEmpty, (Plate[leftNotFull].size()==0)?leftNotFull-1:leftNotFull);
+    }
+
+    int pop() {
+        if (rightNotEmpty==-1)
+            return -1;
+        return popAtStack(rightNotEmpty);
+    }
+
+    int popAtStack(int index) {
+        if (Plate[index].size()==0)
+            return -1;
+
+        int ret = Plate[index].back();
+        Plate[index].pop_back();
+
+        if (index==rightNotEmpty && Plate[rightNotEmpty].size()==0)
+        {
+            while (Plate[rightNotEmpty].size()==0 && rightNotEmpty>=0)
+                rightNotEmpty--;
+        }
+
+        leftNotFull = min(leftNotFull, index);
+
+        return ret;
+    }
+};
+
+/**
+ * Your DinnerPlates object will be instantiated and called as such:
+ * DinnerPlates* obj = new DinnerPlates(capacity);
+ * obj->push(val);
+ * int param_2 = obj->pop();
+ * int param_3 = obj->popAtStack(index);
+ */
+
+
+