Submission #243698

#	Time	Username	Problem	Language	Result	Execution time	Memory
243698		Lawliet	Paint By Numbers (IOI16_paint)	C++17	100 / 100	1037 ms	90224 KiB

paint

#include "paint.h"
#include <bits/stdc++.h>

using namespace std;

const int MAXK = 110;
const int MAXN = 200010;

int n, k;

int sWhite[MAXN];
int canWhite[MAXN];
int canBlack[MAXN];

bool prefix[MAXN][MAXK][2];
bool suffix[MAXN][MAXK][2];

int qtdWhite(int L, int R) { return sWhite[R] - sWhite[L - 1]; }

string solve_puzzle(string s, vector<int> c)
{
	n = (int)s.size(); k = (int)c.size();

	c.insert( c.begin() , -1 );
	s.insert( s.begin() , 'o' );

	for(int i = 1 ; i <= n ; i++)
	{
		sWhite[i] = sWhite[i - 1];
		if( s[i] == '_' ) sWhite[i]++;
	}

	prefix[0][0][0] = prefix[0][0][1] = true;
	suffix[n + 1][k + 1][0] = suffix[n + 1][k + 1][1] = true;

	for(int j = 0 ; j <= k ; j++)
	{
		for(int i = 1 ; i <= n ; i++)
		{
			if( s[i] == '_' || s[i] == '.' )
			{
				prefix[i][j][0] = prefix[i - 1][j][1];
				prefix[i][j][1] = prefix[i - 1][j][1];
			}

			if( j == 0 || i - c[j] < 0 ) continue;
			if( qtdWhite( i - c[j] + 1 , i ) != 0 ) continue;

			if( s[i] == 'X' || s[i] == '.' )
				prefix[i][j][1] = prefix[i][j][1] || prefix[i - c[j]][j - 1][0];
		}
	}

	for(int j = k + 1 ; j > 0 ; j--)
	{
		for(int i = n ; i > 0 ; i--)
		{
			if( s[i] == '_' || s[i] == '.' )
			{
				suffix[i][j][0] = suffix[i + 1][j][1];
				suffix[i][j][1] = suffix[i + 1][j][1];
			}

			if( j == k + 1 || i + c[j] > n + 1 ) continue;
			if( qtdWhite( i , i + c[j] - 1 ) != 0 ) continue;

			if( s[i] == 'X' || s[i] == '.' )
				suffix[i][j][1] = suffix[i][j][1] || suffix[i + c[j]][j + 1][0];
		}
	}

	for(int i = 1 ; i <= n ; i++)
		for(int j = 0 ; j <= k ; j++)
			if( prefix[i - 1][j][1] && suffix[i + 1][j + 1][1] ) canWhite[i]++;

	for(int j = 1 ; j <= k ; j++)
	{
		int sum = 0;

		for(int R = 1 ; R <= n ; R++)
		{
			int L = R - c[j] + 1;

			if( L <= 0 || qtdWhite( L , R ) != 0 ) continue;

			if( prefix[L - 1][j - 1][0] && suffix[R + 1][j + 1][0] )
			{
				canBlack[L]++;
				canBlack[R + 1]--;
			}
		}
	}

	for(int i = 1 ; i <= n ; i++)
		canBlack[i] += canBlack[i - 1];

	string ans;

	for(int i = 1 ; i <= n ; i++)
	{
		if( s[i] != '.' )
		{
			ans.push_back( s[i] );
			continue;
		}

		if( canWhite[i] > 0 && canBlack[i] > 0 ) ans.push_back( '?' );
		if( canWhite[i] > 0 && canBlack[i] == 0 ) ans.push_back( '_' );
		if( canWhite[i] == 0 && canBlack[i] > 0 ) ans.push_back( 'X' );
	}

	return ans;
}

Compilation message (stderr)

paint.cpp: In function 'std::__cxx11::string solve_puzzle(std::__cxx11::string, std::vector<int>)':
paint.cpp:78:7: warning: unused variable 'sum' [-Wunused-variable]
   int sum = 0;
       ^~~

• Subtask 1: 7 / 7
• Subtask 2: 3 / 3
• Subtask 3: 22 / 22
• Subtask 4: 27 / 27
• Subtask 5: 21 / 21
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10