aboutsummaryrefslogtreecommitdiff
path: root/merge_lists.cpp
blob: b57bf5363d02e704464f963ea1e157eacd40b052 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
#include <bits/stdc++.h>
#include <cstddef>

struct ListNode {
  int val;
  ListNode *next;
  ListNode() : val(0), next(nullptr) {}
  ListNode(int x) : val(x), next(nullptr) {}
  ListNode(int x, ListNode *next) : val(x), next(next) {}
};

class Solution {
public:
  ListNode *mergeTwoLists(ListNode *list1, ListNode *list2) {
    if (list1 == NULL)
      return list2;
    if (list2 == NULL)
      return list1;
    if (list1->val <= list2->val) {
      list1->next = mergeTwoLists(list1->next, list2);
      return list1;
    } else {
      list2->next = mergeTwoLists(list1, list2->next);
      return list2;
    }
  }
};

int main() {}