牛客练习赛31 D神器大师泰兹瑞与威穆

双链表搞完了

#include<bits/stdc++.h>
using namespace std;
#define maxn 1000005
int tot,bac[maxn],fa[maxn];
char a[maxn],b[maxn];
int main(){
   cin>>(a+1);
   cin>>(b+1);
   tot=0;
   //cout<<strlen(a)<<endl;
   int la=strlen(a+1),lb=strlen(b+1);
   for(int j=0;j<=la;j++){
      fa[j]=tot-1;
      if(j==strlen(a+1))
        bac[j]=-1;
      else bac[j]=++tot;

      //cout<<j<<" "<<fa[j]<<" "<<bac[j]<<endl;
   }
   bool i=0;
   int z=1;
   for(int j=1;j<=lb;j++){
      if(i>0){
         if(b[j]=='e'){
           i=0;
           continue;
         }
         int l=fa[z];
         a[++tot]=b[j];
         fa[tot]=l;
         bac[tot]=z;
         fa[z]=tot;
         bac[l]=tot;
         z=bac[tot];

      }else{
        if(b[j]=='i'){
           i=1;
           continue;
        }
        else if(b[j]=='x'){
           int l=fa[z];
           int r=bac[z];
           //cout<<l<<" "<<r<<endl;
           if(r!=-1){
             fa[r]=l;
             bac[l]=r;
             z=bac[l];
           }else{
             z=l;
             bac[l]=-1;
           }
        }
        else if(b[j]=='f'){
           char c=b[j+1];
           for(int ii=bac[z];ii!=-1;ii=bac[ii]){
              if(a[ii]==c){
                 z=ii;
                 break;
              }
           }
           j++;
        }
        else if(b[j]=='l'){
           if(bac[z]!=-1)
             z=bac[z];
        }
        else if(b[j]=='h'){
           z=fa[z];
           if(z==0) z=bac[z];
        }
      }
   }
   int q=0;
   while(q!=-1){
      q=bac[q];
      cout<<a[q];
   }
}