From da63dcb16bda368e33cc3531e6e0f90444c5d97b Mon Sep 17 00:00:00 2001
From: Sainnhe Park <i@sainnhe.dev>
Date: Mon, 14 Nov 2022 11:57:10 +0800
Subject: [PATCH] s0024

---
 include/s0024_swap_nodes_in_pairs.hpp | 17 +++++++++++++++++
 src/s0024_swap_nodes_in_pairs.cpp     | 11 +++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 include/s0024_swap_nodes_in_pairs.hpp
 create mode 100644 src/s0024_swap_nodes_in_pairs.cpp

diff --git a/include/s0024_swap_nodes_in_pairs.hpp b/include/s0024_swap_nodes_in_pairs.hpp
new file mode 100644
index 0000000..88e0a0b
--- /dev/null
+++ b/include/s0024_swap_nodes_in_pairs.hpp
@@ -0,0 +1,17 @@
+#ifndef S0024_SWAP_NODES_IN_PAIRS
+#define S0024_SWAP_NODES_IN_PAIRS
+
+struct ListNode {
+  int val;
+  ListNode* next;
+  ListNode() : val(0), next(nullptr) {}
+  ListNode(int x) : val(x), next(nullptr) {}
+  ListNode(int x, ListNode* next) : val(x), next(next) {}
+};
+
+class Solution {
+ public:
+  ListNode* swapPairs(ListNode* head);
+};
+
+#endif
diff --git a/src/s0024_swap_nodes_in_pairs.cpp b/src/s0024_swap_nodes_in_pairs.cpp
new file mode 100644
index 0000000..3a59528
--- /dev/null
+++ b/src/s0024_swap_nodes_in_pairs.cpp
@@ -0,0 +1,11 @@
+#include "s0024_swap_nodes_in_pairs.hpp"
+
+ListNode* swapPairs(ListNode* head) {
+  if (head == nullptr || head->next == nullptr) {
+    return head;
+  }
+  ListNode *newHead = head->next;
+  head->next = swapPairs(newHead->next);
+  newHead->next = head;
+  return newHead;
+}