24.两两交换链表中的节点 (二刷)

Author: w2xi

vs-lt/24.两两交换链表中的节点.js

@@ -0,0 +1,43 @@
+/*
+ * @lc app=leetcode.cn id=24 lang=javascript
+ *
+ * [24] 两两交换链表中的节点
+ */
+
+// @lc code=start
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+var swapPairs = function(head) {
+  if (!head || !head.next) {
+    return head;
+  }
+  const dummyNode = new ListNode(0, head);
+  let prev = dummyNode;
+  let curr = head;
+
+  // 1 -> 2 -> 3 -> 4
+  // => 
+  // 2 -> 1 -> 4 -> 3
+
+  while (curr && curr.next) {
+    const temp = curr.next.next;
+    prev.next = curr.next;
+    curr.next.next = curr;
+    curr.next = temp;
+    prev = curr;
+    curr = temp;
+  }
+
+  return dummyNode.next;
+};
+// @lc code=end
+