[LINKED LISTS]: C++ solution to "medium" puzzle "Sum of Linked Lists".

From https://www.algoexpert.io/questions/Sum%20of%20Linked%20Lists

Linked Lists/sum-of-linked-lists.cpp

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+/*!
+ * @brief Sum of Linked Lists
+ *        From https://www.algoexpert.io/questions/Sum%20of%20Linked%20Lists
+ */
+
+class LinkedList {
+public:
+  int value;
+  LinkedList* next{nullptr};
+
+  LinkedList(int p_val) : value(p_val) { }
+};
+
+LinkedList* sumOfLinkedLists(LinkedList* l1,
+                             LinkedList* l2) {
+    LinkedList *ret{new LinkedList(0)}, *cur{ret};
+    int carry{0};
+    while ( l1 || l2 || carry ) {
+        cur->next  = new LinkedList(carry);
+        cur        = cur->next;
+        carry      = 0;
+        if ( l1 ) { cur->value += l1->value; l1 = l1->next; }
+        if ( l2 ) { cur->value += l2->value; l2 = l2->next; }
+
+        if ( cur->value >= 10 ) { cur->value -= 10; carry = 1; }
+    }
+
+    return ret->next;
+}