218. 연결 리스트에서 짝지어 값 교환

1#include <stdio.h>
2 
3struct Node {
4    int val;
5    struct Node *next;
6};
7 
8int main() {
9    struct Node e = {5, NULL};
10    struct Node d = {1, &e};
11    struct Node c = {8, &d};
12    struct Node b = {3, &c};
13    struct Node a = {7, &b};
14    struct Node *p = &a;
15    int t;
16    while (p != NULL && p->next != NULL) {
17        t = p->val;
18        p->val = p->next->val;
19        p->next->val = t;
20        p = p->next->next;
21    }
22    for (p = &a; p != NULL; p = p->next) {
23        printf("%d ", p->val);
24    }
25    printf("\n");
26    return 0;
27}