go
package main

import "fmt"

type ListNode struct {
    Val  int
    Next *ListNode
}

func getIntersectionNode(headA, headB *ListNode) *ListNode {
    if headA == nil || headB == nil {
        return nil
    }

    // 计算链表长度
    lenA := 0
    lenB := 0
    currA, currB := headA, headB

    for currA != nil {
        lenA++
        currA = currA.Next
    }
    for currB != nil {
        lenB++
        currB = currB.Next
    }

    // 对齐起点
    currA, currB = headA, headB
    if lenA > lenB {
        for i := 0; i < lenA-lenB; i++ {
            currA = currA.Next
        }
    } else {
        for i := 0; i < lenB-lenA; i++ {
            currB = currB.Next
        }
    }

    // 同步遍历直到找到相交节点或遍历结束
    for currA != nil && currB != nil {
        if currA == currB {
            return currA
        }
        currA = currA.Next
        currB = currB.Next
    }

    return nil
}

// 测试代码
func main() {
    // 构造链表A: 1 -> 2 -> 3 \
    //                         6 -> 7
    //            4 -> 5     /
    // 链表B:          4 -> 5 /
    common := &ListNode{6, &ListNode{7, nil}}
    headA := &ListNode{1, &ListNode{2, &ListNode{3, common}}}
    headB := &ListNode{4, &ListNode{5, common}}

    intersection := getIntersectionNode(headA, headB)
    if intersection != nil {
        fmt.Printf("相交节点值: %d\n", intersection.Val)
    } else {
        fmt.Println("没有相交节点")
    }
}