Create main.cpp

Author: JawadSher

19 - Heap Data Structure Problems/15 - Smallest Range Covering Element from K Lists/main.cpp

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+class Node {
+    public:
+        int data;
+        int row;
+        int col;
+
+        Node(int data, int row, int col) { 
+            this->data = data;
+            this->row = row;
+            this->col = col;
+        }
+};
+
+class compare{
+    public:
+        bool operator()(Node* a, Node* b){
+            return a -> data > b -> data;
+        }
+};
+class Solution {
+public:
+    vector<int> smallestRange(vector<vector<int>>& nums) {
+        int k = nums.size();
+
+        priority_queue<Node*, vector<Node*>, compare> pq;
+
+        int mini = INT_MAX;
+        int maxi = INT_MIN;
+
+        for(int i = 0; i < k; i++){
+            int element = nums[i][0];
+
+            maxi = max(maxi, element);
+            mini = min(mini, element);
+
+            pq.push(new Node(element, i, 0));
+        }
+
+        int start = mini;
+        int end = maxi;
+
+        while(!pq.empty()){
+            Node* temp = pq.top();
+            pq.pop();
+
+            mini = temp -> data;
+
+            if(maxi - mini < end - start){
+                start = mini;
+                end = maxi;
+            }
+
+            if(temp -> col + 1 < nums[temp -> row].size()){
+                int nextElement = nums[temp -> row][temp -> col + 1];
+
+                maxi = max(nextElement, maxi);
+                pq.push(new Node(nextElement, temp -> row, temp -> col + 1));
+            }else{
+                break;
+            }
+        }
+
+        return {start, end};
+    }
+};