Submission #133800

#	Time	Username	Problem	Language	Result	Execution time	Memory
133800		claudy	Crayfish scrivener (IOI12_scrivener)	C++14	100 / 100	701 ms	133772 KiB

scrivener

//# pragma GCC optimize("Ofast,no-stack-protector")
//# pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
//# pragma GCC optimize("Ofast")
//# pragma GCC optimization ("unroll-loops")
# include "bits/stdc++.h"
/*
# include <ext/pb_ds/tree_policy.hpp>
# include <ext/pb_ds/assoc_container.hpp>
# include <ext/rope>
*/
std::pair<int,int> DR[] = {{-1,0},{0,1},{1,0},{0,-1},{-1,1},{-1,-1},{1,1},{1,-1}};
# define ll long long
# define clock (clock() * 1000.0 / CLOCKS_PER_SEC)
# define rc(s) return cout << s,0
# define rcg(s) cout << s;exit(0)
# define _ ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
# define db(x) cerr << #x << " = " << x << '\n'
# define pb push_back
# define mp make_pair
# define all(s) s.begin(),s.end()
# define sz(x) (int)((x).size())
//# define int ll
using namespace std;

char val[1 << 20];
int p[1 << 20][20];
vector<int>vec;
int curr,k;
int dep[1 << 20];
int nxt[1 << 20][26];

void Init()
{
	vec.pb(0);
}

void TypeLetter(char L)
{
	if(!nxt[curr][L - 'a']) 
	{
		nxt[curr][L - 'a'] = ++k;
		dep[k] = dep[curr] + 1;
		val[k] = L;
		p[k][0] = curr;
		for(int i = 1;i <= 20;i++)
		{
			p[k][i] = p[p[k][i - 1]][i - 1];
		}
		curr = k;
	}
	else curr = nxt[curr][L - 'a'];
	vec.pb(curr);
}

void UndoCommands(int U)
{
	curr = vec[sz(vec) - U - 1];
	vec.pb(curr);
}

char GetLetter(int P)
{
	int y = dep[curr] - P - 1;
	int x = curr;
	for(int i = 0;i <= 20;i++)
	{
		if(y & (1 << i))
		{
			x = p[x][i];
		}
	}
	return val[x];
}

Compilation message (stderr)

scrivener.cpp: In function 'void TypeLetter(char)':
scrivener.cpp:47:12: warning: iteration 19 invokes undefined behavior [-Waggressive-loop-optimizations]
    p[k][i] = p[p[k][i - 1]][i - 1];
    ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
scrivener.cpp:45:19: note: within this loop
   for(int i = 1;i <= 20;i++)
                 ~~^~~~~

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