import java.io.*;
import java.util.*;
public class mecho {
public static void main(String[] args) throws IOException {
BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
//BufferedReader bf = new BufferedReader(new FileReader("tester.in"));
PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));
StringTokenizer stk = new StringTokenizer(bf.readLine());
int N = Integer.parseInt(stk.nextToken());
int S = Integer.parseInt(stk.nextToken());
String[][] grid = new String[N][N];
LinkedList<pair> list = new LinkedList<>();
int[][] bees = new int[N][N];
int startx = 0, starty = 0, homex = 0, homey = 0;
for(int i = 0; i < N; i++){
String line = bf.readLine();
String[] str = line.split("");
Arrays.fill(bees[i], Integer.MAX_VALUE);
for(int c = 0; c < N; c++){
grid[i][c] = str[c];
if(grid[i][c].equals("H")){
list.add(new pair(i, c, 0));
bees[i][c] = 0;
}
if(grid[i][c].equals("M")){
startx = i;
starty = c;
}
if(grid[i][c].equals("D")){
homex = i;
homey = c;
}
}
}
int[] dx = new int[]{0, 1, 0, -1};
int[] dy = new int[]{1, 0, -1, 0};
boolean[][] visited = new boolean[N][N];
while(!list.isEmpty()){
pair p = list.pop();
if(p.x == homex && p.y == homey)continue;
if(grid[p.x][p.y].equals("T"))continue;
bees[p.x][p.y] = Math.min(bees[p.x][p.y], p.t+S);
if(visited[p.x][p.y])continue;
visited[p.x][p.y] = true;
for(int i = 0; i < 4; i++){
int nx = p.x+dx[i];
int ny = p.y+dy[i];
if(N <= nx || nx < 0 || N <= ny || ny < 0)continue;
list.add(new pair(nx, ny, bees[p.x][p.y]));
}
counter++;
}
bees[homex][homey] = Integer.MAX_VALUE;
int start = 0, end = 10000000;
while(start != end){
int mid = (start+end+1)/2;
if(verify(bees, grid, mid, startx, starty, homex, homey, N, S))start = mid;
else end = mid-1;
}
System.out.println(start);
}
public static boolean verify(int[][] bees, String[][] grid, int time, int startx, int starty, int homex, int homey, int N, int S){
Stack<pair> stack = new Stack<>();
stack.push(new pair(startx, starty, time*S));
int[] dx = new int[]{0, 1, 0, -1};
int[] dy = new int[]{1, 0, -1, 0};
TreeSet<pair> visited = new TreeSet<>();
while(!stack.isEmpty()){
pair p = stack.pop();
if(p.t >= bees[p.x][p.y])continue;
if(visited.contains(p))continue;
visited.add(p);
for(int i = 0; i < 4; i++){
int nx = p.x+dx[i];
int ny = p.y+dy[i];
if(N <= nx || nx < 0 || N <= ny || ny < 0)continue;
if(bees[nx][ny] <= p.t)continue;
if(grid[nx][ny].equals("T")||grid[nx][ny].equals("H"))continue;
if(bees[nx][ny] <= p.t+1)continue;
stack.push(new pair(nx, ny, p.t+1));
}
}
stack = null;
dx = null;
dy = null;
for(pair p:visited){
if(p.x == homex && p.y == homey){
visited = null;
return true;
}
}
return false;
}
public static class pair implements Comparable<pair>{
int x, y, t;
public pair(int a, int b, int c){
x = a;
y = b;
t = c;
}
@Override
public int compareTo(pair o) {
if(x==o.x&&y==o.y)return Integer.compare(t, o.t);
if(x==o.x)return Integer.compare(y, o.y);
return Integer.compare(x, o.x);
}
public boolean equals(pair o){
if(x == o.x && y == o.y && t == o.t)return true;
return false;
}
}
}
Compilation message
mecho.java:52: error: cannot find symbol
counter++;
^
symbol: variable counter
location: class mecho
1 error
