Submission #1274366

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274366		ishaanthenerd	Tracks in the Snow (BOI13_tracks)	C++20	11.04 / 100	2099 ms	82856 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;

bool inBounds(int x, int y, int r, int c) {
    return x >= 0 && x < r && y >= 0 && y < c;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int h, w;
    cin >> h >> w;
    vector<vector<char>> grid(h, vector<char>(w));
    vector<vector<int>> score(h, vector<int>(w, INT_MAX));
    
    score.at(0).at(0) = 1;
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            cin >> grid.at(i).at(j);
        }
    }
    
    queue<pii> q;
    q.push({0, 0});
    while (!q.empty()) {
        pii p = q.front();
        q.pop();
        int x = p.first, y = p.second;
        for (int k = -2; k < 2; k++) {
            int dx = k % 2, dy = (k + 1) % 2;
            if (inBounds(x + dx, y + dy, h, w) && score.at(x).at(y) + (grid.at(x).at(y) != grid.at(x + dx).at(y + dy)) < score.at(x + dx).at(y + dy) && !(x + dx == h - 1 && y + dy == w - 1)) {
                score.at(x + dx).at(y + dy) = score.at(x).at(y) + (grid.at(x).at(y) != grid.at(x + dx).at(y + dy));
                q.push({x + dx, y + dy});
            }
        }
    }
    int ans = 0;
    for (int i = 0; i < h; i++) for (int j = 0; j < (i + 1 == h ? w - 1 : w); j++) ans = max(ans, score.at(i).at(j));
    cout << ans << endl;
    
    return 0;
}

• Subtask 1: 6.6667 / 30
• Subtask 2: 4.375 / 70