Submission #226258

#	Time	Username	Problem	Language	Result	Execution time	Memory
226258		staniewzki	Paint By Numbers (IOI16_paint)	C++17	100 / 100	536 ms	8644 KiB

paint

#include<bits/stdc++.h>
using namespace std;
 
#define REP(i, n) for(int i = 0; i < n; i++)
#define FOR(i, a, b) for(int i = a; i <= b; i++)
 
#include "paint.h"

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

	vector<int> w(n);
	REP(i, n) 
		w[i] = (s[i] == '_') + (i != 0 ? w[i - 1] : 0);

	auto get = [&](int l, int r) {
		return w[r] - (l != 0 ? w[l - 1] : 0);
	};

	vector<vector<bool>> suff(k + 1, vector<bool>(n + 1));
	suff[k][n] = true;
	for(int i = k; i >= 0; i--) {
	 	for(int j = n - 1; j >= 0; j--) {
			if(s[j] != 'X' && suff[i][j + 1])
				suff[i][j] = true;
			if(i < k) {
				int r = j + c[i] - 1;
				if(n <= r || get(j, r)) continue;
				if(i < k - 1 && (n <= r + 1 || s[r + 1] == 'X')) continue; 
				if(suff[i + 1][(i < k - 1 ? r + 1 : r) + 1])
					suff[i][j] = true;
			}
		}
	}

	vector<int> f(n + 1), e(n + 1);
	vector<vector<bool>> pref(k + 1, vector<bool>(n + 1));
	pref[0][0] = true;
	REP(i, k + 1) REP(j, n) {
		if(!pref[i][j]) continue;
		if(s[j] != 'X') {
			pref[i][j + 1] = true;
			if(suff[i][j + 1]) e[j] = true;
		}
		if(i < k) {
			int r = j + c[i] - 1;
			if(n <= r || get(j, r)) continue;
			if(i < k - 1 && (n <= r + 1 || s[r + 1] == 'X')) continue;

			int p = (i < k - 1 ? r + 1 : r);
			pref[i + 1][p + 1] = true;
			if(suff[i + 1][p + 1]) {
				f[j]++, f[r + 1]--;
				if(i < k - 1) e[p] = true;
			}
		}
	}

	FOR(i, 1, n)
		f[i] += f[i - 1];

	string ans;
	REP(i, n) {
		if(e[i] && f[i]) ans += "?";
		else if(e[i]) ans += "_";
		else ans += "X";
	}

	return ans;
}

• 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