[Rope] bzoj1269 [ahoi2006] Text Editor

To maintain a string, you can perform the following operations:

 
 
It mainly refers to segment insertion, segment deletion, and segment flip. The first two operations are implemented through rope. The third operation is not difficult. Maintain two ropes, one forward and the other backward. When you flip, you just need to swap. Rope Tutorial: http://blog.csdn.net/iamzky/article/details/38348653 code (orz zky ):

 1 #include<cstdio> 2 #include<ext/rope> 3 using namespace std; 4 using namespace __gnu_cxx; 5 crope a,b,tmp; 6 int n,p,sz,len,res; 7 char op[21],s[2000001],r[2000001],c; 8 inline int getint(){res=0;c=‘*‘;while(c<‘0‘||c>‘9‘)c=getchar();while(c>=‘0‘&&c<=‘9‘){res=res*10+(c-‘0‘);c=getchar();}return res;} 9 int main()10 {11     scanf("%d",&n);12     for(;n>0;n--)13       {14           scanf("%s",op);15           if(op[0]==‘M‘)p=getint();16           else if(op[0]==‘P‘)p--;17         else if(op[0]==‘N‘)p++;18           else if(op[0]==‘G‘){putchar(a[p]);putchar(‘\n‘);}19           else if(op[0]==‘I‘)20             {21                 sz=getint();22                 len=a.length();23                 for(int i=0;i<sz;i++){24                   do{s[i]=getchar();}while(s[i]==‘\n‘);25                   r[sz-i-1]=s[i];26                 }27             s[sz]=r[sz]=‘\0‘;28             a.insert(p,s);29             b.insert(len-p,r);30             }31           else if(op[0]==‘D‘)32             {33               sz=getint();34             len=a.length();35             a.erase(p,sz);36             b.erase(len-p-sz,sz);37             }38           else if(op[0]==‘R‘)39             {40                 sz=getint();41             len=a.length();42             tmp=a.substr(p,sz);43             a=a.substr(0,p)+b.substr(len-p-sz,sz)+a.substr(p+sz,len-p-sz);44             b=b.substr(0,len-p-sz)+tmp+b.substr(len-p,p);45             }46       }47     return 0;48 }

 

[Rope] bzoj1269 [ahoi2006] Text Editor