Advanced Typewriter (tries)

Problem 1 Advanced Typewriter (TYPE.CPP/C/PAS)

"topic description"

The early seedling started with the latest advanced typewriter. The latest nature has a different function with the past, that is, it has the function of revocation, powerful bar.

Design a program for this advanced typewriter that supports the following 3 types of operations:

1.T x: Lay a lowercase letter x at the end of the article. (Type operation)

2.U x: Undo the last X modification operation. (Undo operation)

(Note that the query operation does not count as a modification operation)

3.Q x: Ask for the first X letter in the current article and output. (Query action)

The article can be considered an empty string at the beginning.

"Input Format"

Line 1th: An integer n that represents the number of operations.

The following n rows, one command per line. Ensure that the commands entered are valid.

"Output Format"

Output a letter per line that represents the answer to the query action.

"Sample Input"

7

T A

T b

T C

Q 2

U 2

T C

Q 2

"Sample Output"

B

C

"Data Range"

For 40% of the data n<=200;

For 100% of the data n<=100000; guarantee that the undo operation does not undo the undo operation.

< advanced challenges >

The undo operation can be undone for 200% data n<=100000;undo operations.

<ioi Challenge >

You must use an online algorithm to complete the problem.

The problem is to be used in the dictionary tree (tries)

There are MSM (multiplication algorithm)

Add another point

Char S[0] or Char

scanf ("%s", s)

This sentence will not save the ""

So I'm going to turn the loop's self variable i into 0.

#include <cstdio> #include <cstring> #include <cstdlib> #include <iostream> #include <cmath
> #include <vector> #include <cctype> using namespace std;
#define MAXN (100000+10) #define LOGMAXN (16+10) int n,tot=0;
	struct Tnode {int DEEP,F[LOGMAXN];
	Char Edge;
		Tnode () {memset (f,0,sizeof (f));
		Deep=-1;
	Edge= ' ";
		} tnode (char _edge,int _fa,int _deep) {memset (f,0,sizeof (f));
		F[0]=_FA;
		Edge=_edge;	
	Deep=_deep;
	int Logdeep () {return int (trunc log (deep)/log (2));
}}NODE[MAXN];
	int log2 (int a) {return int (trunc (log (a)/log (2))} void MSM (Tnode &a) {int n=a.logdeep ();//if (n==1) return;
	for (int i=1;i<=n;i++) {a.f[i]=node[a.f[i-1]].f[i-1];
	} void Type () {char C;
	scanf ("%s", &c);
	tot++;
	Node[tot]=tnode (c,tot-1,node[tot-1].deep+1);
MSM (Node[tot]);
	} void Quere () {int p;
	scanf ("%d", &p);
	Tnode Now=node[tot]; P=now.deep+1-p;
		The first I ' s ancestor while (p) {int i=log2 (p);
		p-= (1<<i); now=Node[now.f[i]]; 
	 
printf ("%c\n", Now.edge);
	} void Undo () {int p;
	scanf ("%d", &p);
	tot++;
NODE[TOT]=NODE[TOT-1-P];
	int main () {freopen ("type.in", "R", stdin);
	Freopen ("Type.out", "w", stdout);
	scanf ("%d", &n);
	Node[0]=tnode ();
		for (int ii=1;ii<=n;ii++) {//printf ("%d\n", ii);
Char s[10];
		printf ("%d\n", ii);
scanf ("%s", s);
printf ("%d\n", ii);
		while (1);
			Switch (S[0]) {case ' T ': type ();
			Case ' U ': Undo ();			
		Case ' Q ': Quere ();
	}//while (1);
return 0;
 }