Submission #69141

#	Time	Username	Problem	Language	Result	Execution time	Memory
69141		Navick	Paint By Numbers (IOI16_paint)	C++17	100 / 100	675 ms	141540 KiB

paint

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

#define F first
#define S second
#define pii pair<int, int>
#define pb push_back

using namespace std;

const int maxN = 2e5 + 10, maxK = 102;

bool wh[maxN], bl[maxN], dp[maxN][maxK], pd[maxN][maxK], sh[maxN][maxK];
int ps[maxN], sum[maxK][maxN], ps2[maxN];

std::string solve_puzzle(std::string s, std::vector<int> c) {
    int n = s.size(), k = c.size();
	
	for (int i=0; i<n; i++) {
		ps[i + 1] = ps[i] + (s[i] == '_');
		ps2[i + 1] = ps2[i] + (s[i] == 'X');
	}

	dp[0][0] = 1;

	for (int i=1; i<=n; i++)
		for (int j=0; j<=k; j++)
		{
			if(j == 0)
			{
				dp[i][j] = (ps2[i] == 0);
				continue ;
			}

			if(s[i - 1] == '_' || s[i - 1] == '.') dp[i][j] = dp[i - 1][j];

			if((s[i - 1] == 'X' || s[i - 1] == '.') && i >= c[j - 1])
			{
				int td = ps[i] - ps[i - c[j - 1]];
				if(td == 0 && (i - c[j - 1] - 1 < 0 || s[i - c[j - 1] - 1] != 'X')) {
					dp[i][j] |= dp[max(0, i - c[j - 1] - 1)][j - 1];
					sh[i][j] = dp[max(0, i - c[j - 1] - 1)][j - 1];
				}
			}
			//cout << i << ',' << j << " --> " << sh[i][j] << endl;
		}

	pd[n][k] = 1;
	
	for (int i=n-1; i>=0; i--)
		for (int j=k; j>=0; j--)
		{

			if(j == k)
			{
				pd[i][j] = (ps2[n] - ps2[i] == 0);
				continue ;
			}

			if(s[i] == '_' || s[i] == '.') pd[i][j] = pd[i + 1][j];

			if((s[i] == 'X' || s[i] == '.') && n - i >= c[j])
			{
				int td = ps[i + c[j]] - ps[i];
				if(td == 0 && (i + c[j] >= n || s[i + c[j]] != 'X')) 
					pd[i][j] |= pd[min(n, i + c[j] + 1)][j + 1];
			}
		}

	for (int i=0; i<n; i++)
	{
		if(s[i] == '.')
		{
			for (int j=0; j<=k; j++)
				wh[i] |= (dp[i][j] && pd[i + 1][j]);
			//cout << i << " --> " << wh[i] << endl;
		}
	}
	
	for (int i=1; i<=n; i++)
		for (int j=1; j<=k; j++)
		{
			sum[j][i] = sum[j][i - 1];
			if(!sh[i][j]) continue ;
			if(i >= n || (s[i] != 'X'))
				sh[i][j] = pd[min(n, i + 1)][j];
			else sh[i][j] = 0;
		
			sum[j][i] += sh[i][j];
		}

	for (int i=0; i<n; i++)
	{
		if(s[i] != '.') continue ;
		for (int j=1; j<=k; j++) {
			int td = sum[j][min(n, i + c[j - 1])] - sum[j][i];
			if(td) bl[i] = true;
		}

		//cout << i << " <>>> " << bl[i] << endl;

	}
	
	for (int i=0; i<n; i++)
	{
		if(s[i] == '.')
			if(wh[i] && bl[i]) s[i] = '?';
			else if(wh[i]) s[i] = '_';
			else if(bl[i]) s[i] = 'X';
	}

	return s;
}

Compilation message (stderr)

paint.cpp: In function 'std::__cxx11::string solve_puzzle(std::__cxx11::string, std::vector<int>)':
paint.cpp:107:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   if(s[i] == '.')
     ^

• 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