Submission #784383

#	Time	Username	Problem	Language	Result	Execution time	Memory
784383		raysh07	Portals (BOI14_portals)	C++17	20 / 100	21 ms	28120 KiB

portals

#include <bits/stdc++.h>
using namespace std;
#define INF (int)1e9

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

int n, m;
const int N = 1005;
bool a[N][N];
int d[N][N];
int x, y;
vector <pair<int, int>> ok[N][N];

void Solve()
{
	cin >> n >> m;

	queue <pair<int, int>> q;

	for (int i = 1; i <= n; i++){
		string s; cin >> s;

		for (int j = 1; j <= m; j++){
			ok[i][j].push_back({i - 1, j});
			ok[i][j].push_back({i, j + 1});
			ok[i][j].push_back({i + 1, j});
			ok[i][j].push_back({i, j - 1});
			d[i][j] = INF;
			if (s[j - 1] == 'S'){
				a[i][j] = true;
				d[i][j] = 0;
				q.push({i, j});
			} else if (s[j - 1] == 'C'){
				a[i][j] = true;
				x = i;
				y = j;
			} else if (s[j - 1] == '.'){
				a[i][j] = true;
			}
		}
	}

	for (int i = 1; i <= n; i++){
		int last = 0;
		for (int j = 1; j <= m; j++){
			ok[i][j].push_back({i, last});
			if (!a[i][j]) last = 0;
			else if (last == 0) last = j;
		}

		last = 0;
		for (int j = m; j >= 1; j--){
			ok[i][j].push_back({i, last});
			if (!a[i][j]) last = 0;
			else if (last == 0) last = j;
		}
	}

	for (int j = 1; j <= m; j++){
		int last = 0;
		for (int i = 1; i <= n; i++){
			ok[i][j].push_back({last, j});
			if (!a[i][j]) last = 0;
			else if (last == 0) last = i;
		}

		last = 0;
		for (int i = n; i >= 1; i--){
			ok[i][j].push_back({last, j});
			if (!a[i][j]) last = 0;
			else if (last == 0) last = i;
		}
	}

	while (!q.empty()){
		auto pi = q.front(); q.pop();
		int ux = pi.first, uy = pi.second;
	//	cout << ux << " " << uy << "\n";

		for (auto [vx, vy] : ok[ux][uy]){
		    if (!a[vx][vy]) continue;
			if (d[vx][vy] == INF){
				d[vx][vy] = d[ux][uy] + 1;
				q.push({vx, vy});
			}
		}
	}

	cout << d[x][y] << "\n";
}

int32_t main() 
{
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;

   // freopen("in",  "r", stdin);
   // freopen("out", "w", stdout);

  //  cin >> t;
    for(int i = 1; i <= t; i++) 
    {
        //cout << "Case #" << i << ": ";
        Solve();
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
    return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30