cavity-map.java

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Solution {

  // Complete the cavityMap function below.
  static String[] cavityMap(String[] grid) {
    ArrayList<Integer> x = new ArrayList<Integer>();
    ArrayList<Integer> y = new ArrayList<Integer>();
    for (int i = 1; i < grid.length - 1; i++) {
      for (int j = 1; j < grid[i].length() - 1; j++) {
        Character c = grid[i].charAt(j);
        Character t = grid[i - 1].charAt(j);
        Character b = grid[i + 1].charAt(j);
        Character l = grid[i].charAt(j - 1);
        Character r = grid[i].charAt(j + 1);
        if (c > t && c > b && c > l && c > r) {
          x.add(i); y.add(j);
        }
      }
    }
    for (int i = 0; i < x.size(); i++) {
      grid[x.get(i)] =
          grid[x.get(i)].substring(0, y.get(i)) +
              "X" +
              grid[x.get(i)].substring(y.get(i) + 1, grid[x.get(i)].length());
    }
    return grid;
  }

  private static final Scanner scanner = new Scanner(System.in);

  public static void main(String[] args) throws IOException {
    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

    int n = scanner.nextInt();
    scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

    String[] grid = new String[n];

    for (int i = 0; i < n; i++) {
      String gridItem = scanner.nextLine();
      grid[i] = gridItem;
    }

    String[] result = cavityMap(grid);

    for (int i = 0; i < result.length; i++) {
      bufferedWriter.write(result[i]);

      if (i != result.length - 1) {
        bufferedWriter.write("\n");
      }
    }

    bufferedWriter.newLine();

    bufferedWriter.close();

    scanner.close();
  }
}