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 =998244353;
const int N =100010;
#define clc(a,b) memset(a,b,sizeof(a))
const double eps = 1e-7;
void fre() {freopen("in.txt","r",stdin);}
void freout() {freopen("out.txt","w",stdout);}
inline int read() {int x=0,f=1;char ch=getchar();while(ch>'9'||ch<'0') {if(ch=='-') f=-1;ch=getchar();}while(ch>='0'&&ch<='9') {x=x*10+ch-'0';ch=getchar();}return x*f;}
int n;
int sta[3][N],top[3];
char op[10],s[5],s1[5];
int x[N];
void fun(){
    top[0]=top[1]=top[2]=0;
    for(int i=0;i<n;i++){
        scanf("%s%s",op,s);
        int a=s[0]-'A';
        if(op[1]=='u'){
           scanf("%d",&x[i]);
           sta[a][top[a]++]=i;
        }
        else if(op[1]=='o'){
            if(!top[a]) a=2;
            printf("%d\n",x[sta[a][--top[a]]]);
        }
        else {
            scanf("%s",s1);
            top[2]=merge(sta[0],sta[0]+top[0],sta[1],sta[1]+top[1],sta[2]+top[2])-sta[2];
            top[0]=top[1]=0;
        }
    }
}
int main(){
    int cas=1;
    while(~scanf("%d",&n),n){
        printf("Case #%d:\n", cas++);
        fun();
    }
    return 0;
}