增加新题目

链表/两两交换链表中的节点/main.go

@@ -0,0 +1,54 @@
+package main
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func main() {
+
+}
+
+func swapPairs(head *ListNode) *ListNode {
+
+	firstNode := (*ListNode)(head)
+	secondNode := (*ListNode)(nil)
+	num := 0
+	for head != nil {
+		if head.Next != nil {
+			if head.Next.Next != nil {
+				if num == 0 {
+					firstNode = head.Next
+					secondNode = head
+				}
+				if secondNode != nil && num != 0 {
+					secondNode.Next = head.Next
+				}
+				tmpright := head.Next.Next
+				head.Next.Next = head
+				head.Next = tmpright
+				secondNode = head
+				head = tmpright
+
+				num++
+				continue
+			} else {
+				if num == 0 {
+					firstNode = head.Next
+					secondNode = head
+				}
+				if secondNode != nil && num != 0 {
+					secondNode.Next = head.Next
+				}
+				tmpright := head.Next.Next
+				head.Next.Next = head
+				secondNode = head
+				head.Next = tmpright
+
+			}
+		}
+		head = head.Next
+		num++
+	}
+	return firstNode
+}