Submission #907611

#	Time	Username	Problem	Language	Result	Execution time	Memory
907611		cogentcoder73	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	772 ms	126460 KiB

tracks

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

const int INF = 2147483647;

int main() {
    int H, W;
    cin >> H >> W;

    vector<string> meadow(H);
    for (int i = 0; i < H; i++) cin >> meadow[i];

    vector<vector<int>> dists(H, vector<int>(W, INF));
    dists[0][0] = 1;
    deque<pair<int, int>> q; q.push_back({0, 0});
    pair<int, int> cur; char curC, newC;

    while (!q.empty()) {
        cur = q.front();
        q.pop_front();
        curC = meadow[cur.first][cur.second];

        if (cur.first > 0) {
            newC = meadow[cur.first - 1][cur.second];
            if (newC == curC) {
                if (dists[cur.first][cur.second] < dists[cur.first - 1][cur.second]) {
                    dists[cur.first - 1][cur.second] = dists[cur.first][cur.second];
                    q.push_front({cur.first - 1, cur.second});
                }
            } else if (newC != '.') {
                if (dists[cur.first][cur.second] + 1 < dists[cur.first - 1][cur.second]) {
                    dists[cur.first - 1][cur.second] = dists[cur.first][cur.second] + 1;
                    q.push_back({cur.first - 1, cur.second});
                }
            }
        }

        if (cur.first < H - 1) {
            newC = meadow[cur.first + 1][cur.second];
            if (newC == curC) {
                if (dists[cur.first][cur.second] < dists[cur.first + 1][cur.second]) {
                    dists[cur.first + 1][cur.second] = dists[cur.first][cur.second];
                    q.push_front({cur.first + 1, cur.second});
                }
            } else if (newC != '.') {
                if (dists[cur.first][cur.second] + 1 < dists[cur.first + 1][cur.second]) {
                    dists[cur.first + 1][cur.second] = dists[cur.first][cur.second] + 1;
                    q.push_back({cur.first + 1, cur.second});
                }
            }
        }

        if (cur.second > 0) {
            newC = meadow[cur.first][cur.second - 1];
            if (newC == curC) {
                if (dists[cur.first][cur.second] < dists[cur.first][cur.second - 1]) {
                    dists[cur.first][cur.second - 1] = dists[cur.first][cur.second];
                    q.push_front({cur.first, cur.second - 1});
                }
            } else if (newC != '.') {
                if (dists[cur.first][cur.second] + 1 < dists[cur.first][cur.second - 1]) {
                    dists[cur.first][cur.second - 1] = dists[cur.first][cur.second] + 1;
                    q.push_back({cur.first, cur.second - 1});
                }
            }
        }

        if (cur.second < W - 1) {
            newC = meadow[cur.first][cur.second + 1];
            if (newC == curC) {
                if (dists[cur.first][cur.second] < dists[cur.first][cur.second + 1]) {
                    dists[cur.first][cur.second + 1] = dists[cur.first][cur.second];
                    q.push_front({cur.first, cur.second + 1});
                }
            } else if (newC != '.') {
                if (dists[cur.first][cur.second] + 1 < dists[cur.first][cur.second + 1]) {
                    dists[cur.first][cur.second + 1] = dists[cur.first][cur.second] + 1;
                    q.push_back({cur.first, cur.second + 1});
                }
            }
        }
    }

    int ans = 1;
    for (int i = 0; i < H; i++) {
        for (int j = 0; j < W; j++) {
            if (dists[i][j] != INF) ans = max(ans, dists[i][j]);
        }
    }

    cout << ans << "\n";
    return 0;
}

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