Submission #250619

#	Time	Username	Problem	Language	Result	Execution time	Memory
250619		opukittpceno_hhr	Portals (BOI14_portals)	C++17	100 / 100	876 ms	127608 KiB

portals

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <fstream>
#include <cassert>
#include <cstring>
#include <unordered_set>
#include <unordered_map>
#include <numeric>
#include <ctime>
#include <bitset>
#include <complex>
#include <chrono>
#include <random>
#include <functional>

using namespace std;

const int N = 1010;
const int INF = 1e9 + 239;
const vector<int> dx = {1, -1, 0, 0};
const vector<int> dy = {0, 0, 1, -1};

int n, m;
int a[N][N];

int d[N * N];
vector<pair<int, int>> g[N * N];

int ok(int i, int j) {
	return 0 <= i && i < n && 0 <= j && j < m && !a[i][j];
}

int get(int i, int j) {
	return i * m + j;
}

void dij(int st) {
	fill(d, d + n * m, INF);
	d[st] = 0;
	set<pair<int, int>> s;
	s.insert({d[st], st});
	while (!s.empty()) {
		int v = s.begin()->second;
		s.erase(s.begin());
		for (auto [u, w] : g[v]) {
			if (d[u] > d[v] + w) {
				s.erase({d[u], u});
				d[u] = d[v] + w;
				s.insert({d[u], u});
			}
		}
	}
}

int cu[N][N];
int cd[N][N];
int cl[N][N];
int cr[N][N];

void init() {
	for (int i = 0; i < n; i++) {
		cl[i][0] = 0;
		for (int j = 1; j < m; j++) {
			if (!a[i][j]) {
				cl[i][j] = 1 + cl[i][j - 1];
			} else {
				cl[i][j] = 0;
			}
		}
		cr[i][m - 1] = 0;
		for (int j = m - 2; j >= 0; j--) {
			if (!a[i][j]) {
				cr[i][j] = 1 + cr[i][j + 1];
			} else {
				cr[i][j] = 0;
			}
		}
	}
	for (int j = 0; j < m; j++) {
		cu[0][j] = 0;
		for (int i = 1; i < n; i++) {
			if (!a[i][j]) {
				cu[i][j] = 1 + cu[i - 1][j]; 
			} else {
				cu[i][j] = 0;
			}
		}
		cd[n - 1][j] = 0;
		for (int i = n - 2; i >= 0; i--) {
			if (!a[i][j]) {
				cd[i][j] = 1 + cd[i + 1][j];
			} else {
				cd[i][j] = 0;
			}
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (!a[i][j]) {
				cl[i][j]--;
				cr[i][j]--;
				cu[i][j]--;
				cd[i][j]--;
			}
		}
	}
}

signed main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < N; j++) {
			a[i][j] = 1;
		}
	}
	int si = -1;
	int sj = -1;
	int ci = -1;
	int cj = -1;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			char c;
			cin >> c;
			a[i][j] = (c == '#');
			if (c == 'S') {
				si = i;
				sj = j;
			}
			if (c == 'C') {
				ci = i;
				cj = j;
			}
		}
	}
	n += 2;
	m += 2;
	init();
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (a[i][j]) continue;
			int mn = min({cu[i][j], cd[i][j], cl[i][j], cr[i][j]});
			g[get(i, j)].push_back({get(i - cu[i][j], j), 1 + mn});
			g[get(i, j)].push_back({get(i + cd[i][j], j), 1 + mn});
			g[get(i, j)].push_back({get(i, j - cl[i][j]), 1 + mn});
			g[get(i, j)].push_back({get(i, j + cr[i][j]), 1 + mn});
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			for (int k = 0; k < 4; k++) {
				if (ok(i, j) && ok(i + dx[k], j + dy[k])) {
					g[get(i, j)].push_back({get(i + dx[k], j + dy[k]), 1});
				}
			}
		}
	}
	dij(get(si, sj));
	cout << d[get(ci, cj)] << endl;
}

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