Submission #31197

#	Time	Username	Problem	Language	Result	Execution time	Memory
31197		pasa3232	Crayfish scrivener (IOI12_scrivener)	C++14	100 / 100	699 ms	128132 KiB

scrivener

#include<bits/stdc++.h>
using namespace std;

int now, A[1000010], d[30][1000010], lev[1000010];
char L[1000010];

char last;

void Init() {
    for(int i=0; i<30; i++) for(int j=0; j<1000010; j++) d[i][j]=-1;
}

void TypeLetter(char La) {
    A[++now]=now;
    lev[now]=lev[A[now-1]]+1;
    L[now]=La;
    d[0][now]=A[now-1];
    for(int i=1; d[i-1][d[i-1][now]]!=-1; i++) d[i][now]=d[i-1][d[i-1][now]];
}

void UndoCommands(int U) {
    A[++now]=A[now-U-1];
}

char GetLetter(int P) {
    int b=P;
    b=lev[A[now]]-b-1;
    int rev=A[now];
    while(b){
        int i, num;
        for(i=0, num=1; num<=b; i++, num*=2);
        i--;
        b-=(num/2);
        rev=d[i][rev];
    }
    return L[rev];

}

Compilation message (stderr)

scrivener.cpp: In function 'void TypeLetter(char)':
scrivener.cpp:14:17: warning: operation on 'now' may be undefined [-Wsequence-point]
     A[++now]=now;
                 ^
scrivener.cpp: In function 'void UndoCommands(int)':
scrivener.cpp:22:24: warning: operation on 'now' may be undefined [-Wsequence-point]
     A[++now]=A[now-U-1];
                        ^

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 22 / 22
• Subtask 4: 26 / 26
• Subtask 5: 40 / 40