题目描述

哈希表方法

样例

func copyRandomList(head *ListNode) *ListNode {
    r := make(map[*ListNode]*ListNode)
    t := &ListNode{Val: 0, Next: nil, Random: nil}
    s := head
    ans := t
    for head != nil {
        t.Next = &ListNode{Val: head.Val, Next: nil, Random: nil}
        t = t.Next
        r[head] = t
        head = head.Next
    }
    for s != nil {
        if s.Random != nil {
            r[s].Random = r[s.Random]

        }
        s = s.Next
    }
    return ans.Next
}