Submission #69123

#	Time	Username	Problem	Language	Result	Execution time	Memory
69123		MatheusLealV	Portals (BOI14_portals)	C++17	0 / 100	35 ms	30724 KiB

portals

#include <bits/stdc++.h>
#define N 1050
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;

int n, m, xo, yo, xi, yi, dx[4] = {1, -1, 0, 0}, dy[4] = {0, 0, 1, -1};

int id[N][N], cnt, dist[N*N], pai[N*N];

pii O[N];

char mat[N][N];

vector<pii> grafo[N*N];

inline int solve(int ini, int fim)
{
	priority_queue<pii, vector<pii>, greater<pii> > fila;

	memset(dist, 0x3f3f3f3f, sizeof dist);

	dist[ini] = 0;

	fila.push({0, ini});

	while(!fila.empty())
	{
		int x = fila.top().s, d = fila.top().s;

		fila.pop();

		if(d > dist[x]) continue;

		for(auto v: grafo[x])
		{
			if(dist[v.f] > dist[x] + v.s)
			{
				dist[v.f] = dist[x] + v.s;

				pai[v.f] = x;

				fila.push({dist[v.f], v.f});
			}
		}
	}

	int u = fim;

	return dist[fim];
}

pii esq[N][N], dir[N][N], baixo[N][N], cima[N][N];

inline void fill()
{
	for(int i = 1; i <= n; i++)
	{
		int ultimo = 0;

		for(int j = 1; j <= m; j++)
		{
			if(mat[i][j] == '#') ultimo = j;

			esq[i][j] = {i, ultimo + 1};
		}

		ultimo = m + 1;

		for(int j = m; j >= 1; j--)
		{
			if(mat[i][j] == '#') ultimo = j;

			dir[i][j] = {i, ultimo - 1};			
		}
	}

	for(int j = 1; j <= m; j++)
	{
		int ultimo = 0;

		for(int i = 1; i <= n; i++)
		{
			if(mat[i][j] == '#') ultimo = i;

			cima[i][j] = {ultimo + 1, j};
		}

		ultimo = n + 1;

		for(int i = n; i >= 1; i --)
		{
			if(mat[i][j] == '#') ultimo = i;

			baixo[i][j] = {ultimo - 1, j};
		}
	}
}

int main()
{
	ios::sync_with_stdio(false); cin.tie(0);

	cin>>n>>m;

	for(int i = 0; i <= n + 1; i++)
	{
		for(int j = 0; j <= m + 1; j++)
		{
			id[i][j] = ++ cnt;

			O[id[i][j]] = {i, j};
		}
	}

	for(int i = 0; i <= n + 1; i++)
		for(int j = 0; j <= m + 1; j++)
		{
			if(!i or i == n + 1 or !j or j == m + 1)
			{
				mat[i][j] = '#';

				continue;
			}

			cin>>mat[i][j];

			if(mat[i][j] == 'S') xo = i, yo = j;

			if(mat[i][j] == 'C') xi = i, yi = j;
		}

	for(int i = 1; i <= n; i++)
	{
		for(int j = 1; j <= m; j++)
		{
			int x = id[i][j];

			if(mat[i][j] != '#')
			{
				for(int p = 0; p < 4; p++)
				{
					int a = i + dx[p], b = j + dy[p];

					if(a < 0 or b < 0 or a > n + 1 or b > m + 1) continue;

					 if(mat[a][b] != '#') grafo[x].push_back({id[a][b], 1}); 
				}
			}
		}
	}

	fill();

	for(int i = 1; i <= n; i++)
	{
		for(int j = 1; j <= m; j++)
		{
			if(mat[i][j] == '#') continue;

			vector< pii > pos;

			pos.push_back(esq[i][j]), pos.push_back(dir[i][j]);

			pos.push_back(baixo[i][j]), pos.push_back(cima[i][j]);

			int x = id[i][j], custo = 2000000000;

			for(int a = 0; a < pos.size(); a++)
			{
				int A = abs(i - pos[a].f) + abs(j - pos[a].s);

				custo = min(custo, A + 1);
			}

			for(int a = 0; a < pos.size(); a++) grafo[x].push_back({id[pos[a].f][pos[a].s], custo});
		}
	}

	cout<<solve(id[xo][yo], id[xi][yi])<<"\n";
}

Compilation message (stderr)

portals.cpp: In function 'int solve(int, int)':
portals.cpp:49:6: warning: unused variable 'u' [-Wunused-variable]
  int u = fim;
      ^
portals.cpp: In function 'int main()':
portals.cpp:170:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int a = 0; a < pos.size(); a++)
                   ~~^~~~~~~~~~~~
portals.cpp:177:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int a = 0; a < pos.size(); a++) grafo[x].push_back({id[pos[a].f][pos[a].s], custo});
                   ~~^~~~~~~~~~~~

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