Bitmap.java

/**
 * @Author Mehdi Maick
 * Created on 15/09/2016.
 */

import java.util.*;
import java.io.*;

public class BitMap {

    static class Pair {
        int x, y;

        public Pair(int x, int y) {
            this.x = x;
            this.y = y;
        }
    }

    static char[][] s;
    static int[][] ans;
    static int INF = 999999;
    static int dx[] = {1, -1, 0, 0};
    static int dy[] = {0, 0, -1, 1};

    public static void solve(FastReader fs, PrintWriter pw) {
        int t = fs.nextInt();
        while (t-- > 0) {
            
            int n = fs.nextInt();
            int m = fs.nextInt();
            ans = new int[n + 1][m + 1];
            s = new char[n][];
            Deque<Integer> row = new ArrayDeque<>();
            Deque<Integer> col = new ArrayDeque<>();
            
            for (int i = 0; i < n; i++) {
                s[i] = fs.next().toCharArray();
                for (int j = 0; j < s[i].length; j++) {
                    if (s[i][j] == '1') {
                        row.add(i);
                        col.add(j);
                        ans[i][j] = 0;
                    } else {
                        ans[i][j] = INF;
                    }
                }
            }
            minDist(row, col);
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    pw.print(ans[i][j] + " ");
                }
                pw.println();
            }


        }
    }

    static void minDist(Deque<Integer> row, Deque<Integer> col) {
        int n = ans.length;
        int m = ans[0].length;
        int dist = 1;
        int lev = row.size(), next = 0;
        while (row.peek() != null) {
            int r = row.poll();
            int c = col.poll();
            lev--;
            for (int i = 0; i < 4; i++) {
                int u = r + dx[i];
                int v = c + dy[i];
                if (u < 0 || v < 0) continue;
                if (u > n || v > m) continue;
                if (ans[u][v] > dist) {
                    ans[u][v] = dist;
                    row.offer(u);
                    col.offer(v);
                    next++;
                }
            }

            if (lev == 0) {
                lev = next;
                next = 0;
                dist++;
            }
        }
    }

    public static void main(String[] args) throws Exception {
        FastReader fs = new FastReader(System.in);
        PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));

        solve(fs, pw);

        fs.close();
        pw.close();
    }

    static class FastReader {

        BufferedReader reader;
        StringTokenizer st;

        FastReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream));
            st = null;
        }

        String next() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    String line = reader.readLine();
                    if (line == null) {
                        return null;
                    }
                    st = new StringTokenizer(line);
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String s = null;
            try {
                s = reader.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return s;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        char nextChar() {
            return next().charAt(0);
        }

        int[] nextIntArray(int n) {
            int[] arr = new int[n];
            int i = 0;
            while (i < n) {
                arr[i++] = nextInt();
            }
            return arr;
        }

        long[] nextLongArray(int n) {
            long[] arr = new long[n];
            int i = 0;
            while (i < n) {
                arr[i++] = nextLong();
            }
            return arr;
        }

        int[] nextIntArrayOneBased(int n) {
            int[] arr = new int[n + 1];
            int i = 1;
            while (i <= n) {
                arr[i++] = nextInt();
            }
            return arr;
        }

        long[] nextLongArrayOneBased(int n) {
            long[] arr = new long[n + 1];
            int i = 1;
            while (i <= n) {
                arr[i++] = nextLong();
            }
            return arr;
        }

        void close() {
            try {
                reader.close();
            } catch (IOException e) {
                System.err.println("There's been an error trying closing the reader ");
                e.printStackTrace();
            }
        }
    }


}