Submission #484934

#	Time	Username	Problem	Language	Result	Execution time	Memory
484934		Olympia	Tracks in the Snow (BOI13_tracks)	C++17	82.50 / 100	2098 ms	45360 KiB

tracks

#include <vector>
#include <iostream>
#include <cassert>
#include <cmath>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <set>
#include <algorithm>
#include <iomanip>

using namespace std;
vector<vector<bool>> hasVisited;
vector<string> grid;
vector<pair<int, int>> pos = {{0,  1},
                              {-1, 0},
                              {0,  -1},
                              {1,  0}};

int main() {
    //freopen("milkorder.in", "r", stdin);
    //freopen("milkorder.out", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m;
    cin >> n >> m;
    priority_queue<pair<int, pair<int, int>>> q;
    grid.resize(n), hasVisited.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> grid[i];
        hasVisited[i].resize(m);
        for (int j = 0; j < m; j++) {
            hasVisited[i][j] = false;
        }
    }
    q.push({0, {0, 0}});
    int myMax = 0;
    while (!q.empty()) {
        pair<int, int> loc = q.top().second;
        int dist = -q.top().first;
        myMax = max(myMax, dist);
        q.pop();
        if (hasVisited[loc.first][loc.second]) {
            continue;
        }
        hasVisited[loc.first][loc.second] = true;
        for (auto p: pos) {
            int dx = p.first;
            int dy = p.second;
            if (dx + loc.first >= 0 && dy + loc.second >= 0 && dx + loc.first < n && dy + loc.second < m
                && grid[loc.first + dx][loc.second + dy] != '.') {
                if (hasVisited[loc.first + dx][loc.second + dy]) {
                    myMax = max(myMax, dist + (grid[dx + loc.first][dy + loc.second] != grid[loc.first][loc.second]));
                    continue;
                }
                q.push(make_pair(-dist - (grid[dx + loc.first][dy + loc.second] != grid[loc.first][loc.second]),
                                 make_pair(loc.first + dx, loc.second + dy)));
            }
        }
    }
    cout << myMax;
}

• Subtask 1: 30 / 30
• Subtask 2: 52.5 / 70