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;
}
}
}