#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#define inbuf_len 1 << 16
#define outbuf_len 1 << 16
#include <bits/stdc++.h>
using namespace std;
const int N=1e6+55;
int trie[N*2][26];
char letter[N];
int p[N][22];
int a[N];
int l[N];
int node;
int cnt=1;
int k=1;
void Init()
{
node=cnt++;
}
int c,temp,nd;
void TypeLetter(char L)
{
c=L-'a';
temp=node;
if(trie[node][c]==0)
trie[node][c]=cnt++;
node=trie[node][c];
letter[node]=L;
a[k]=node;
l[k]=l[k-1]+1;
if(p[node][0]==0)
{
p[node][0]=temp;
for(int i=1;i<21;i++)
{
p[node][i]=p[p[node][i-1]][i-1];
if(p[node][i]==0)
break;
}
}
k++;
}
void UndoCommands(int U)
{
node=a[k-U-1];
l[k]=l[k-U-1];
a[k]=node;
k++;
}
char GetLetter(int P)
{
P=l[k-1]-P-1;
nd=node;
for(int i=20;i>=0;i--)
{
if((P&(1<<i)))
nd=p[nd][i];
}
return letter[nd];
}
int main() {
Init();
int cmd_num;
int tmp=1;
tmp = scanf("%d", &cmd_num);
assert(tmp == 1);
int i;
for (i = 0; i < cmd_num; i++) {
char cmd;
tmp = scanf(" %c", &cmd);
assert(tmp == 1);
if (cmd == 'T') {
char letter;
tmp = scanf(" %c", &letter);
assert(tmp == 1);
TypeLetter(letter);
}
else if (cmd == 'U') {
int number;
tmp = scanf("%d", &number);
assert(tmp == 1);
UndoCommands(number);
}
else if (cmd == 'P') {
int index;
char letter;
tmp = scanf("%d", &index);
assert(tmp == 1);
letter = GetLetter(index);
printf("%c\n", letter);
}
}
return 0;
}
Compilation message
/tmp/ccQ45AM6.o: In function `main':
scrivener.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/cc0GsqHL.o:grader.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status
