Submission #1222279

#	Time	Username	Problem	Language	Result	Execution time	Memory
1222279		OmarAlimammadzade	Awesome Arrowland Adventure (eJOI19_adventure)	C++20	100 / 100	41 ms	5564 KiB

adventure

#include <bits/stdc++.h>
using namespace std;

const int N = 501;
const int dx[] = { -1, 0, 1, 0 }, dy[] = { 0, 1, 0, -1 };
int arrow[N][N], dis[N][N], n, m;

int dijkstra() {
    dis[1][1] = 0;
    priority_queue<array<int, 3>> q;
    q.push({ 0, 1, 1 });
    while (q.size()) {
        auto [d, x, y] = q.top();
        q.pop();
        d = -d;
        if (x == n and y == m) {
            return d;
        }
        if (d != dis[x][y] or arrow[x][y] == -1) {
            continue;
        }
        for (int i = 0; i < 4; i++) {
            int w = (i - arrow[x][y] + 4) % 4;
            int nx = x + dx[i], ny = y + dy[i];
            if (nx < 1 or n < nx or ny < 1 or m < ny) {
                continue;
            }
            if (dis[nx][ny] > dis[x][y] + w) {
                dis[nx][ny] = dis[x][y] + w;
                q.push({ -dis[nx][ny], nx, ny });
            }
        }
    }
    return -1;
}

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(nullptr);
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            char c;
            cin >> c;
            arrow[i][j] = (c == 'N' ? 0 : c == 'E' ? 1 : c == 'S' ? 2 : c == 'W' ? 3 : -1);
            dis[i][j] = 1e9;
        }
    }
    cout << dijkstra() << '\n';
}

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 12 / 12
• Subtask 4: 16 / 16
• Subtask 5: 50 / 50