Submission #1116530

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116530		xnqs	Nautilus (BOI19_nautilus)	C++17	66 / 100	1067 ms	2700 KiB

nautilus

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi2,popcnt,lzcnt")

#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <cstring>

int x, y, p;
char arr[505][505];
char moves[5005];
int dp[2][505][505];

const int dx[] = {0,1,0,-1};
const int dy[] = {1,0,-1,0};

inline int in_mat(int i, int j) {
	return !(i<0||i>=x||j<0||j>=y);
}

void solve_dp() {
	for (int pos = 0; pos <= p; pos++) {
		int curr_pos = pos&1;
		int last_pos = curr_pos^1;
		for (int i = 0; i < x; i++) {
			for (int j = 0; j < y; j++) {
				if (arr[i][j]=='#') {
					dp[curr_pos][i][j] = 0;
					continue;
				}
				if (pos==0) {
					dp[curr_pos][i][j] = 1;
					continue;
				}

				dp[curr_pos][i][j] = 0;
				switch (moves[pos-1]) {
				case 'N':
					dp[curr_pos][i][j] = ((in_mat(i+1,j)) ? dp[last_pos][i+1][j] : 0);
					break;
				case 'S':
					dp[curr_pos][i][j] = ((in_mat(i-1,j)) ? dp[last_pos][i-1][j] : 0);
					break;
				case 'E':
					dp[curr_pos][i][j] = ((in_mat(i,j-1)) ? dp[last_pos][i][j-1] : 0);
					break;
				case 'W':
					dp[curr_pos][i][j] = ((in_mat(i,j+1)) ? dp[last_pos][i][j+1] : 0);
					break;
				default:
					for (int k = 0; k < 4; k++) {
						int iv = i+dx[k];
						int jv = j+dy[k];
						dp[curr_pos][i][j] |= ((in_mat(iv,jv)) ? dp[last_pos][iv][jv] : 0);
					}
					break;
				}
			}
		}
	}
}

int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(NULL);
	std::cout.tie(NULL);

	std::cin >> x >> y >> p;
	for (int i = 0; i < x; i++) {
		std::cin >> arr[i];
	}
	std::cin >> moves;

	int cnt = 0;
	for (int i = 0; i < p; i++) {
		cnt += (moves[i]!='*');
	}

	if (x>100&y>100&&(double)cnt/p<=0.003) {
		int ans = 0;
		for (int i = 0; i < x; i++) {
			for (int j = 0; j < y; j++) {
				ans += (arr[i][j]!='#');
			}
		}
		std::cout << ans << "\n";
		return 0;
	}

	solve_dp();
	int ret = 0;
	for (int i = 0; i < x; i++) {
		for (int j = 0; j < y; j++) {
			ret += dp[p&1][i][j];
		}
	}

	std::cout << ret << "\n";
}

Compilation message (stderr)

nautilus.cpp: In function 'int main()':
nautilus.cpp:82:7: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   82 |  if (x>100&y>100&&(double)cnt/p<=0.003) {
      |      ~^~~~

• Subtask 1: 29 / 29
• Subtask 2: 37 / 37
• Subtask 3: 0 / 34