Added some code

leetcode/problems/cpp/divisible-and-non-divisible-sums-difference.cpp

@@ -0,0 +1,17 @@
+// by @codeAbinash
+// Time : O(n)
+// Space : O(1)
+
+class Solution {
+ public:
+   int differenceOfSums(int n, int m) {
+      int sum1 = 0, sum2 = 0;
+      for (int i = 1; i <= n; i++) {
+         if (i % m == 0)
+            sum1 += i;
+         else
+            sum2 += i;
+      }
+      return sum2 - sum1;
+   }
+};

leetcode/problems/cpp/kth-smallest-element-in-a-sorted-matrix.cpp

@@ -0,0 +1,22 @@
+// by @codeAbinash
+// Time : O(nlogk)
+// Space : O(k)
+
+#include "queue"
+#include "vector"
+
+using namespace std;
+
+class Solution {
+ public:
+   int kthSmallest(vector<vector<int>>& matrix, int k) {
+      priority_queue<int> pq;
+      for (auto row : matrix) {
+         for (auto num : row) {
+            pq.push(num);
+            if (pq.size() > k) pq.pop();
+         }
+      }
+      return pq.top();
+   }
+};