Submission #1197595

#	Time	Username	Problem	Language	Result	Execution time	Memory
1197595		TahirAliyev	Tracks in the Snow (BOI13_tracks)	C++20	97.81 / 100	1349 ms	1114112 KiB

tracks

#include <bits/stdc++.h>

// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #define int long long
#define ll long long
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
const int oo = 1e9 + 9;
const int MAX = 4000 + 5, LOGMAX = 20, B = 441, MOD = 998244353;

int n, m;
int vis[MAX][MAX][2];
vector<char> ch = {'R', 'F'};
vector<pii> dir = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
vector<pii> s;
vector<pii> add;
string arr[MAX];
 
void dfs(int x, int y, int t){
    vis[x][y][t] = 1;
    if(!vis[x][y][t^1]) add.push_back({x, y});
    for(auto d : dir){
        int nx = x + d.first, ny = y + d.second;
        if(nx < 1 || nx > n || ny < 1 || ny > m || vis[nx][ny][t] || arr[nx][ny] != ch[t]) continue;
        dfs(nx, ny, t);
    }
}

void solve(){
    cin >> n >> m;
    bool r = 0, f = 0;
    for(int i = 1; i <= n; i++){
        cin >> arr[i];
        arr[i] = '%' + arr[i];
    }
    s.push_back({1, 1});
    if(arr[1][1] == '.'){
        cout << "0\n";
        return;
    }
    int ans = -1;
    int t = (arr[1][1] == 'F');
    while(s.size()){
        for(auto a : s){
            if(vis[a.first][a.second][t]){
                add.push_back(a);
                continue;
            } 
            dfs(a.first, a.second, t);
        }
        swap(add, s);
        add.clear();
        ans++;
        t ^= 1;
    }
    cout << ans << '\n';
}   

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    // cin >> t;
    while(t--) solve();
}

• Subtask 1: 30 / 30
• Subtask 2: 67.8125 / 70