Submission #453341

#	Time	Username	Problem	Language	Result	Execution time	Memory
453341		UltraFalcon	Awesome Arrowland Adventure (eJOI19_adventure)	C++17	0 / 100	1 ms	332 KiB

adventure

#include <bits/stdc++.h>
#define int long long

using namespace std;

struct dirs_struct {
    const int INF = 1e18;

    int N = 0;
    int E = 1;
    int S = 2;
    int W = 3;

    int get_dir(char dir) {
        if (dir == 'N') {
            return N;
        } else if (dir == 'E') {
            return E;
        } else if (dir == 'S') {
            return S;
        } else if (dir == 'W') {
            return W;
        } else {
            return -1;
        }
    }

    int get_dir(int dx, int dy) {
        if (dx == 0 && dy == -1) {
            return N;
        } else if (dx == 1 && dy == 0) {
            return E;
        } else if (dx == 0 && dy == 1) {
            return S;
        } else if (dx == -1 && dy == 0) {
            return W;
        } else {
            return -1;
        }
    }

    int get_cost(char direction1, int dx, int dy) {
        int dir1 = get_dir(direction1);
        int dir2 = get_dir(dx, dy);

        if (dir1 == -1 || dir2 == -1) {
            return INF;
        } else {
            return ((dir2 - dir1) + 4) % 4;
        }
    }
};

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    const int INF = 1e18;

    dirs_struct dirs;

    int m, n;
    cin >> m >> n;

    vector<vector<char>> grid(m+2, vector<char>(n+2, 'X'));
    for (int y=0; y<m; y++) {
        for (int x=0; x<n; x++) {
            cin >> grid[y+1][x+1];
        }
    }

    vector<vector<int>> cost(m+2, vector<int>(n+2, INF));
    priority_queue<tuple<int, int, int>,
                   vector<tuple<int, int, int>>,
                   greater<tuple<int, int, int>>> pq;

    cost[1][1] = 0;
    pq.emplace(0, 0, 0);

    while (!pq.empty()) {
        auto [c, x, y] = pq.top();
        pq.pop();

        //cerr << c << " " << x << " " << y << "\n";

        if (grid[y+1][x+1] == 'X') { continue; }

        array<pair<int, int>, 4> offsets {make_pair(1, 0), make_pair(-1, 0), 
                                          make_pair(0, 1), make_pair(0, -1)};

        for (auto [dx, dy] : offsets) {
            int new_cost = c + dirs.get_cost(grid[y+1][x+1], dx, dy);
            if (cost[y+dy+1][x+dx+1] > new_cost) {
                cost[y+dy+1][x+dx+1] = new_cost;
                pq.emplace(new_cost, x+dx, y+dy);
            }
        }
    }

    cout << cost[m][n] << "\n";

}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 12
• Subtask 4: 0 / 16
• Subtask 5: 0 / 50