多校7 HDU5818 Joint Stacks

 多校7 HDU5818 Joint Stacks
 题意：n次操作。模拟栈的操作，合并的以后，每个栈里的元素以入栈顺序排列
 思路：开三个栈，并且用到了merge函数
 O(n)的复杂度

 #include <bits/stdc++.h>
 using namespace std;
 #define LL long long
 const int inf = 0x3f3f3f3f;
 const int MOD =;
 const int N =;
 #define clc(a,b) memset(a,b,sizeof(a))
 const double eps = 1e-;
 void fre() {freopen("in.txt","r",stdin);}
 void freout() {freopen("out.txt","w",stdout);}
 inline int read() {int x=,f=;char ch=getchar();while(ch>''||ch<'') {if(ch=='-') f=-;ch=getchar();}while(ch>=''&&ch<='') {x=x*+ch-'';ch=getchar();}return x*f;}
 int n;
 int sta[][N],top[];
 char op[],s[],s1[];
 int x[N];
 void fun(){
     top[]=top[]=top[]=;
     for(int i=;i<n;i++){
         scanf("%s%s",op,s);
         int a=s[]-'A';
         if(op[]=='u'){
            scanf("%d",&x[i]);
            sta[a][top[a]++]=i;
         }
         else if(op[]=='o'){
             if(!top[a]) a=;
             printf("%d\n",x[sta[a][--top[a]]]);
         }
         else {
             scanf("%s",s1);
             top[]=merge(sta[],sta[]+top[],sta[],sta[]+top[],sta[]+top[])-sta[];
             top[]=top[]=;
         }
     }
 }
 int main(){
     int cas=;
     while(~scanf("%d",&n),n){
         printf("Case #%d:\n", cas++);
         fun();
     }
     return ;
 }