Submission #1203511

#	Time	Username	Problem	Language	Result	Execution time	Memory
1203511		newsboy	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	496 ms	210116 KiB

tracks

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <set>
#include <map>
#include <numeric>
#include <iomanip>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <queue>
#include <deque>
#include <stack>
#include <cmath>
#include <tuple>
#include <cassert>
#include <list>
#include <random>
#include <initializer_list>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
constexpr ld inf = 1e18;
constexpr ll N = 15;
constexpr ll MIN = -inf;
constexpr ll MAX = inf;

struct Point {
    ll x, y;
};

void solve() {
    ll n, m;
    cin >> n >> m;
    vector<string> a(n);
    for (ll i = 0; i < n; ++i) {
        cin >> a[i];
    }
    auto ok = [&](ll x, ll y) -> bool {
        return x > -1 && x < n && y > -1 && y < m && a[x][y] != '.';
        };
    deque<Point> q;
    vector<vector<ll>> d(n, vector<ll> (m, -1));
    vector<ll> dx{ 1, -1, 0, 0 }, dy{ 0, 0, 1, -1 };
    q.push_back({ 0, 0 });
    d[0][0] = 0;
    ll ans = 0;
    while (!q.empty()) {
        Point v = q.front();
        q.pop_front();
        ans = max(ans, d[v.x][v.y]);
        for (ll i = 0; i < 4; ++i) {
            ll x = v.x + dx[i], y = v.y + dy[i];
            if (ok(x, y) && d[x][y] == -1) {
                if (a[x][y] == a[v.x][v.y]) {
                    d[x][y] = d[v.x][v.y];
                    q.push_front({ x, y });
                }
                else {
                    d[x][y] = d[v.x][v.y] + 1;
                    q.push_back({ x, y });
                }
            }
        }
    }
    cout << ans + 1 << '\n';
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
    /*cin >> t;*/
    while (t--) {
        solve();
    }
    return 0;
}

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