intercl lists

#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
  int x;
  struct Node *nxt;
} Node;

Node *mkNode(int x, Node *nxt) {
  Node *node = malloc(sizeof(Node));
  if (node == NULL) {
    perror("");
    exit(-1);
  }
  node->x = x;
  node->nxt = nxt;
  return node;
}

Node *addEnd(Node *node, int x) {
  if (!node) {
    return mkNode(x, NULL);
  }
  Node *p;
  for (p = node; p->nxt; p = p->nxt);
  p->nxt = mkNode(x, NULL);
  return node;
}

void printList(Node *node) {
  for (; node; node = node->nxt) {
    printf("%d ", node->x);
  }
  puts("");
}//*/

void freeList(Node *node) {
  Node *curr = node, *nxt;
  while (curr) {
    nxt = curr->nxt;
    free(curr);
    curr = nxt;
  }
}

Node *readList() {
  int n, x;
  scanf("%d", &n);
  Node *node = NULL;
  for (int i = 0; i < n; i++) {
    scanf("%d", &x);
    node = addEnd(node, x);
  }
  return node;
}

Node *intercl(Node *node1, Node *node2) {
  Node *res = NULL;
  while (node1 && node2) {
    if (node1->x < node2->x) {
      res = addEnd(res, node1->x);
      node1 = node1->nxt;
    } else {
      res = addEnd(res, node2->x);
      node2 = node2->nxt;
    }
  }
  while (node1) {
    res = addEnd(res, node1->x);
    node1 = node1->nxt;
  }
  while (node2) {
    res = addEnd(res, node2->x);
    node2 = node2->nxt;
  }
  return res;
}

int main(void) {
  Node *node1 = readList();
  Node *node2 = readList();
  Node *res = intercl(node1, node2);
  printList(res);
  freeList(res);
  freeList(node1);
  freeList(node2);
  return 0;
}