Submission #1267257

#	Time	Username	Problem	Language	Result	Execution time	Memory
1267257		minhphan	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	788 ms	160696 KiB

tracks

#include <iostream>
#include <deque>
#include <vector>

using namespace std;

int dx[4]{0, 1, 0, -1};
int dy[4]{1, 0, -1, 0};

int main() {
    int H, W;

    cin >> H;
    cin >> W;

    vector<vector<int>> values(W, vector<int>(H, 0));

    deque<pair<int,int>> q;
    q.emplace_back(0, 0);
    values[0][0] = 1;

    vector<vector<int>> grid(W, vector<int>(H, -1));

    for (int i = 0; i<H; i++) {
        string line;
        cin >> line;
        for (int j = 0; j<W; j++) {
            if (line.at(j) == 'F') {
                grid[j][i] = 1;
            } else if (line.at(j) == 'R') {
                grid[j][i] = 0;
            }
        }

    }

    int solution = 1;
    while (!q.empty()) {
        const pair<int, int> el = q.front();
        q.pop_front();

        solution = max(solution, values[el.first][el.second]);

        for (int i = 0; i<4; i++) {
            const int x = el.first + dx[i];
            const int y = el.second + dy[i];
            if (x >= 0 && x<W && y>= 0 && y<H && values[x][y] == 0 && grid[x][y] != -1) {
                if (grid[el.first][el.second] == grid[x][y]) {
                    q.emplace_front(x, y);
                    values[x][y] = values[el.first][el.second];
                } else {
                    q.emplace_back(x, y);
                    values[x][y] = values[el.first][el.second] + 1;
                }
            }
        }
    }

    cout << solution;
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70