Submission #529701

#	Time	Username	Problem	Language	Result	Execution time	Memory
529701		c28dnv9q3	Nautilus (BOI19_nautilus)	C++17	66 / 100	34 ms	2868 KiB

nautilus

#include <vector>
#include <iostream>
#define MAXN 210

char commands[MAXN];
char map[MAXN][MAXN];
char dp[MAXN][MAXN][MAXN];
int R, C, M;

struct pos {
	int x, y;
};

bool recurse(pos p, int a) {
	if (dp[p.x+1][p.y+1][a + 1] != 0) {
		return dp[p.x+1][p.y+1][a + 1] == 2;
	}
	if (p.x < 0 || p.y < 0 || p.x >= R || p.y >= C || map[p.x][p.y] == '#') {
		dp[p.x + 1][p.y + 1][a + 1] = 1;
		return false;
	}
	if (a == -1) {
		return map[p.x][p.y] == '.';
	} else {
		bool r = false;
		switch (commands[a]) {
		case 0:p.x++; r = recurse(p, a - 1); p.x--; break;
		case 1:p.x--; r = recurse(p, a - 1); p.x++; break;
		case 2:p.y--; r = recurse(p, a - 1); p.y++; break;
		case 3:p.y++; r = recurse(p, a - 1); p.y--; break;
		case 4: {
			bool b = false;
			p.x++;
			b = recurse(p, a - 1) || b;
			p.x -= 2;
			b = recurse(p, a - 1) || b;
			p.x++;
			p.y--;
			b = recurse(p, a - 1) || b;
			p.y += 2;
			b = recurse(p, a - 1) || b;
			p.y--;
			r = b;
		}
		}
		dp[p.x + 1][p.y + 1][a + 1] = r ? 2 : 1;
		return r;
	}
}

int main() {
	scanf("%d%d%d", &R, &C, &M);
	getchar();
	for (int i = 0; i < R; i++) {
		for (int j = 0; j < C; j++) {
			char x;
			x = getchar();
			map[i][j] = x;
		}
		getchar();
	}
	for (int i = 0; i < M; i++) {
		char c = getchar();
		int x = -1;
		switch (c) {
		case 'N': x = 0; break;
		case 'S': x = 1; break;
		case 'E': x = 2; break;
		case 'W': x = 3; break;
		case '?': x = 4; break;
		}
		commands[i] = x;
	}

	int counter = 0;
	for (int i = 0; i < R; i++) {
		for (int j = 0; j < C; j++) {
			if (map[i][j] == '.' && recurse({ i,j },M-1)) {
				counter++;
			}
		}
	}
	std::cout << counter;
	return 0;
}

Compilation message (stderr)

nautilus.cpp: In function 'int main()':
nautilus.cpp:52:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |  scanf("%d%d%d", &R, &C, &M);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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