MLASERP - Laser Phones

Tác giả: khuc_tuan

Ngôn ngữ: Java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader kb = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(kb.readLine());
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
		char[][] a = new char[m][];
		for (int i = 0; i < m; ++i)
			a[i] = kb.readLine().toCharArray();
		int[] dx = new int[] { -1, 0, 1, 0 };
		int[] dy = new int[] { 0, -1, 0, 1 };
		Queue<int[]> q = new LinkedList<int[]>();
		int[][][] F = new int[m][n][4];
		int inf = 1000000000;
		for (int[][] a2 : F)
			for (int[] a1 : a2)
				Arrays.fill(a1, inf);
		tt: for (int i = 0; i < m; ++i)
			for (int j = 0; j < n; ++j)
				if (a[i][j] == 'C') {
					for (int k = 0; k < 4; ++k) {
						q.add(new int[] { i, j, k });
						F[i][j][k] = 0;
					}
					break tt;
				}
		while (!q.isEmpty()) {
			int[] fr = q.remove();
			int u = fr[0];
			int v = fr[1];
			int h = fr[2];
			{
				int x = u + dx[h];
				int y = v + dy[h];
				if (x >= 0 && x < m && y >= 0 && y < n && a[x][y] != '*' && F[x][y][h] > F[u][v][h]) {
					F[x][y][h] = F[u][v][h];
					q.add(new int[] { x, y, h });
				}
			}
			for (int k = 0; k < 4; ++k) {
				if (F[u][v][k] > F[u][v][h] + 1) {
					F[u][v][k] = F[u][v][h] + 1;
					q.add(new int[] { u, v, k });
				}
			}
		}
		t2: for (int i = m - 1; i >= 0; --i)
			for (int j = n - 1; j >= 0; --j)
				if (a[i][j] == 'C') {
					int best = inf;
					for (int k = 0; k < 4; ++k)
						best = Math.min(best, F[i][j][k]);
					System.out.println(best);
					break t2;
				}
	}
}

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