problems(cpp): add „48. Rotate Image“

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/rotate-image.cpp

@@ -0,0 +1,18 @@
+#include <algorithm>
+#include <vector>
+
+class Solution {
+public:
+    void rotate(std::vector<std::vector<int>>& matrix)
+    {
+        for (std::size_t i = 0; i < matrix.size(); i++) {
+            for (std::size_t j = i; j < matrix.size(); j++) {
+                std::swap(matrix[i][j], matrix[j][i]);
+            }
+        }
+
+        for (auto& row : matrix) {
+            std::reverse(row.begin(), row.end());
+        }
+    }
+};