合并两个排序的链表

题目描述

输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。

样例输入

1 3 5 7 9

2 4

样例输出

1 2 3 4 5 7 9

package main

import "fmt"

type ListNode struct {
    Val    int
    Next   *ListNode
}

func print(head *ListNode) {
    for head != nil {
        fmt.printf("%d - >", head.Val)
        head = head.Next
    }
}

func MergeTwoList(l1 *ListNode, l2 *ListNode) *ListNode {
    res := &ListNode{}
    cur := res
    for l1 != nil || l2 != nil {
        if l1 == nil {
            cur.Next = l2
            break
        } else if l2 == nil {
            cur.Next = l1
            break
        }
        if l1.Val > l2.Val {
            cur.Next = l2
            cur = cur.Next
            l2 = l2.Next
        } else {
            cur.Next = l1
            cur = cur.Next
            l1 = l1.Next
        }
    }
    return res.Next
}

class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None


class Solution:
    def merge_two_list(self, pHead1, pHead2):
        if pHead1 == None:
            return pHead2
        elif pHead2 == None:
            return pHead1
        
        pMerage = None
        if pHead1.val < pHead2.val:
            pMerage = pHead1
            pMerage.next = self.merge_two_list(pHead1.next, pHead2)
        else:
            pMerage = pHead2
            pMerage.next = self.merge_two_list(pHead1, pHead2.next)
        return pMerage