feat: Nim solution for add two numbers (#502)

Author: yozachar

solution/0000-0099/0002.Add Two Numbers/README.md

@@ -304,6 +304,43 @@ class Solution {
 }
 ```
 
+### **Nim**
+
+```nim
+#[
+    # Driver code in the solution file
+    # Definition for singly-linked list.
+    type
+    Node[int] = ref object
+        value: int
+        next: Node[int]
+
+    SinglyLinkedList[T] = object
+        head, tail: Node[T]  
+]#
+
+# More efficient code churning ...
+proc addTwoNumbers(l1: var SinglyLinkedList, l2: var SinglyLinkedList): SinglyLinkedList[int] =
+  var
+    aggregate: SinglyLinkedList
+    psum: seq[char]
+    temp_la, temp_lb: seq[int]
+
+  while not l1.head.isNil:
+    temp_la.add(l1.head.value)
+    l1.head = l1.head.next
+
+  while not l2.head.isNil:
+    temp_lb.add(l2.head.value)
+    l2.head = l2.head.next
+
+  psum = reversed($(reversed(temp_la).join("").parseInt() + reversed(temp_lb).join("").parseInt()))
+  for i in psum: aggregate.append(($i).parseInt())
+
+  result = aggregate
+```
+
+
 ### **...**
 
 ```

solution/0000-0099/0002.Add Two Numbers/README_EN.md

@@ -292,6 +292,42 @@ class Solution {
 }
 ```
 
+### **Nim**
+
+```nim
+#[
+    # Driver code in the solution file
+    # Definition for singly-linked list.
+    type
+    Node[int] = ref object
+        value: int
+        next: Node[int]
+
+    SinglyLinkedList[T] = object
+        head, tail: Node[T]  
+]#
+
+# More efficient code churning ...
+proc addTwoNumbers(l1: var SinglyLinkedList, l2: var SinglyLinkedList): SinglyLinkedList[int] =
+  var
+    aggregate: SinglyLinkedList
+    psum: seq[char]
+    temp_la, temp_lb: seq[int]
+
+  while not l1.head.isNil:
+    temp_la.add(l1.head.value)
+    l1.head = l1.head.next
+
+  while not l2.head.isNil:
+    temp_lb.add(l2.head.value)
+    l2.head = l2.head.next
+
+  psum = reversed($(reversed(temp_la).join("").parseInt() + reversed(temp_lb).join("").parseInt()))
+  for i in psum: aggregate.append(($i).parseInt())
+
+  result = aggregate
+```
+
 ### **...**
 
 ```

solution/0000-0099/0002.Add Two Numbers/Solution.nim

@@ -0,0 +1,56 @@
+import std/[strutils, algorithm]
+
+type
+  Node[int] = ref object
+    value: int
+    next: Node[int]
+
+  SinglyLinkedList[T] = object
+    head, tail: Node[T]
+
+proc append[T](list: var SinglyLinkedList[T], data: T = nil): void =
+  var node = Node[T](value: data)
+  if list.head.isNil:
+    list.head = node
+    list.tail = node
+  else:
+    list.tail.next = node
+    list.tail = node
+
+proc preview[T](list: SinglyLinkedList[T]): string =
+  var s: seq[T]
+  var n = list.head
+  while not n.isNil:
+    s.add n.value
+    n = n.next
+  result = s.join(" -> ")
+
+proc addTwoNumbers(l1: var SinglyLinkedList, l2: var SinglyLinkedList): SinglyLinkedList[int] =
+  var
+    aggregate: SinglyLinkedList
+    psum: seq[char]
+    temp_la, temp_lb: seq[int]
+
+  while not l1.head.isNil:
+    temp_la.add(l1.head.value)
+    l1.head = l1.head.next
+
+  while not l2.head.isNil:
+    temp_lb.add(l2.head.value)
+    l2.head = l2.head.next
+
+  psum = reversed($(reversed(temp_la).join("").parseInt() + reversed(temp_lb).join("").parseInt()))
+  for i in psum: aggregate.append(($i).parseInt())
+
+  result = aggregate
+
+var list1: SinglyLinkedList[int]
+var list2: SinglyLinkedList[int]
+
+for i in @[2, 4, 3]: list1.append(i)
+for i in @[5, 6, 4]: list2.append(i)
+
+echo(preview(list1))
+echo(preview(list2))
+echo(preview(addTwoNumbers(list1, list2)))
+