ZOJ 4016 Mergeable Stack（from The 18th Zhejiang University Programming Contest Sponsored by TuSimple）

模拟题，用链表来进行模拟

 # include <stdio.h>
 # include <stdlib.h>
 typedef struct node
 {
     int num;
     struct node *q;
     struct node *h;
 }node;
 struct Node
 {
     node *start;
     node *end;
     int sum;
 }m[];
 int main()
 {
     int k;
     scanf("%d", &k);
     while (k--)
     {
         int n, p;
         scanf("%d%d", &n, &p);
         for (int i = ; i <= n; i++)
         {
             m[i].end = NULL;
             m[i].start = NULL;
             m[i].sum = ;
         }
         for (int i = ; i<p; i++)
         {
             int op, s, v, t;
             scanf("%d", &op);
             if (op == )
             {
                 scanf("%d%d", &s, &v);
                 if (m[s].sum == )
                 {
                     m[s].start = (node *)malloc(sizeof(node));
                     m[s].start->num = v;
                     m[s].start->q = NULL;
                     m[s].start->h = NULL;
                     m[s].end = NULL;
                     m[s].sum = ;
                 }
                 else
                 if (m[s].sum == )
                 {
                     m[s].end = (node *)malloc(sizeof(node));
                     m[s].end->num = v;
                     m[s].end->q = m[s].start;
                     m[s].end->h = NULL;
                     m[s].start->h = m[s].end;
                     m[s].sum = ;
                 }
                 else
                 {
                     node * z = (node *)malloc(sizeof(node));
                     z->num = v;
                     z->q = m[s].end;
                     z->h = NULL;
                     m[s].end->h = z;
                     m[s].end = z;
                     m[s].sum++;
                 }
             }
             else
             if (op == )
             {
                 scanf("%d", &s);
                 if (m[s].sum == )
                     printf("EMPTY\n");
                 else
                 {
                     m[s].sum--;
                     if (m[s].sum != )
                         printf("%d\n", m[s].end->num);
                     else
                         printf("%d\n", m[s].start->num);
                     if (m[s].sum != )
                     {
                         node *z = m[s].end->q;
                         z->h = NULL;
                         m[s].end = z;
                     }
                     else
                     {
                         m[s].end = NULL;
                         m[s].start = NULL;
                     }
                 }
             }
             else
             {
                 scanf("%d%d", &s, &t);
                 if (m[s].sum == )
                 {
                     m[s].end = m[t].end;
                     m[s].start = m[t].start;
                     m[s].sum = m[t].sum;
                     m[t].sum = ;
                     m[t].end = NULL;
                     m[t].start = NULL;
                 }
                 else
                 if (m[s].sum == )
                 {
                     m[s].sum += m[t].sum;
                     m[t].sum = ;
                     if (m[t].start != NULL)
                     {
                         m[s].end = m[t].start;
                         m[s].start->h = m[t].start;
                         m[s].end->q = m[s].start;
                         if (m[t].end != NULL)
                             m[s].end = m[t].end;
                         else
                             m[s].end = m[t].start;
                     }
                     m[t].start = NULL;
                     m[t].end = NULL;
                 }
                 else
                 {
                     m[s].sum += m[t].sum;
                     m[t].sum = ;
                     if (m[t].start != NULL)
                     {
                         m[s].end->h = m[t].start;
                         m[t].start->q = m[s].end;
                         if (m[t].end != NULL)
                             m[s].end = m[t].end;
                         else
                             m[s].end = m[t].start;
                     }
                     m[t].start = NULL;
                     m[t].end = NULL;
                 }
             }
         }
     }
     //system("pause");
     return ;
 }