Create 3318. Find X-Sum of All K-Long Subarrays I (#926)

Author: Chayandas07

3318. Find X-Sum of All K-Long Subarrays I

@@ -0,0 +1,53 @@
+class Solution {
+public:
+    int find(map<int, int>& mp, int x){
+  	// Max-heap to store {frequency, number}
+        priority_queue<pair<int, int>> pq;
+        // Build the heap from the frequency map
+        for(auto it: mp){
+            pq.push({it.second, it.first});
+        }
+        int sum=0;
+  	// Get the top x most frequent elements
+        while(x-- && !pq.empty()){
+            auto it = pq.top();
+            pq.pop();
+            int freq = it.first;
+  		// Add all occurrences of this number to the sum
+            while(freq--){
+                sum+=it.second;
+            }
+        }
+        return sum;
+    }
+    vector<int> findXSum(vector<int>& nums, int k, int x) {
+  	// Frequency map for the current window
+        map<int, int> mp;
+  	// Result vector
+        vector<int> v;
+  	// Sliding window pointers
+        int l=0, r=0;
+        while(r<nums.size()){
+  	    // Expand window: add right element
+            mp[nums[r]]++;
+  		// Shrink window if size > k
+            while(l<r && r-l+1 > k){
+  	        // Remove left element from map
+                mp[nums[l]]--;
+  	        // Erase from map if frequency is 0
+                if(mp[nums[l]] == 0){
+                    mp.erase(nums[l]);
+                }
+  	        // Move left pointer
+                l++;
+            }
+  		// If window is exactly size k, process it
+            if(r-l+1 == k){
+                v.push_back(find(mp, x));
+            }
+  		// Move right pointer
+            r++;
+        }
+        return v;
+    }
+};