Submission #961236

#	Time	Username	Problem	Language	Result	Execution time	Memory
961236		MinaRagy06	Paint By Numbers (IOI16_paint)	C++17	90 / 100	2045 ms	42972 KiB

paint

#include <bits/stdc++.h>
#include "paint.h"
#ifdef MINA
#include "grader.cpp"
#endif
using namespace std;
#define ll long long

const int N = 200'005, K = 105;
bool prfdp[N][K], sufdp[N][K];
string solve_puzzle(string s, vector<int> c) {
	int n = s.size(), k = c.size();
	int prf[n + 1]{};
	for (int i = 0; i < n; i++) {
		prf[i + 1] = prf[i] + (s[i] == '_');
	}
	prfdp[0][0] = 1;
	for (int i = 1; i <= n; i++) {
		for (int j = 0; j <= k; j++) {
			if (j - 1 >= 0) {
				if (i - c[j - 1] >= 0 && prf[i] - prf[i - c[j - 1]] == 0) {
					if (j - 1 == 0) {
						prfdp[i][j] = prfdp[i - c[j - 1]][j - 1];
					} else if (s[i - c[j - 1] - 1] != 'X' && i - c[j - 1] - 1 >= 0) {
						prfdp[i][j] = prfdp[i - c[j - 1] - 1][j - 1];
					}
				}
			}
			if (s[i - 1] != 'X') {
				prfdp[i][j] |= prfdp[i - 1][j];
			}
		}
	}
	sufdp[n][k] = 1;
	for (int i = n - 1; i >= 0; i--) {
		for (int j = 0; j <= k; j++) {
			if (j + 1 <= k) {
				if (i + c[j] <= n && prf[i + c[j]] - prf[i] == 0) {
					if (j + 1 == k) {
						sufdp[i][j] = sufdp[i + c[j]][j + 1];
					} else if (i + c[j] + 1 <= n && s[i + c[j]] != 'X') {
						sufdp[i][j] = sufdp[i + c[j] + 1][j + 1];
					}
				}
			}
			if (s[i] != 'X') {
				sufdp[i][j] |= sufdp[i + 1][j];
			}
		}
	}
	string ans;
	ans.resize(n);
	for (int i = 0; i < n; i++) {
		if (s[i] != '.') {
			ans[i] = s[i];
			continue;
		}
		bool ok[2]{};
		for (int j = 0; j < k; j++) {
			for (int l = i; l >= max(0, i - c[j] + 1); l--) {
				if (l + c[j] <= n && prf[l + c[j]] - prf[l] == 0) {
					bool vl = 0, vr = 0;
					if (j == 0) {
						vl = prfdp[l][j];
					} else if (l - 1 >= 0 && s[l - 1] != 'X') {
						vl = prfdp[l - 1][j];
					}
					if (j + 1 == k) {
						vr = sufdp[l + c[j]][j + 1];
					} else if (l + c[j] + 1 <= n && s[l + c[j]] != 'X') {
						vr = sufdp[l + c[j] + 1][j + 1];
					}
					ok[1] |= vl && vr;
				}
			}
		}
//		cout << prfdp[i][0] << ' ' << sufdp[i + 1][0] << '\n';
		for (int j = 0; j <= k; j++) {
			ok[0] |= prfdp[i][j] && sufdp[i + 1][j];
		}
		if (ok[0] && ok[1]) {
			ans[i] = '?';
		} else if (ok[0]) {
			ans[i] = '_';
		} else if (ok[1]) {
			ans[i] = 'X';
		} else {
			assert(0);
		}
	}
	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: 0 / 10