Count Unguarded Cells in the Grid LeetCode solution in Java

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class Solution {
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  public int countUnguarded(int m, int n, int[][] guards, int[][] walls) {
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    int[][] dirs = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
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    char[][] grid = new char[m][n];
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    int count = m * n - guards.length - walls.length;
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    for (int[] wall : walls) {
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      int x = wall[0], y = wall[1];
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      grid[x][y] = 'W';
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    }
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    for (int[] guard : guards) {
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      int x = guard[0], y = guard[1];
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      grid[x][y] = 'G';
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    }
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    for (int[] point : guards) {
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      for (int dir[] : dirs) {
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        int x = point[0] + dir[0];
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        int y = point[1] + dir[1];
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        while (!(x < 0 || y < 0 || x >= m || y >= n || grid[x][y] == 'G' || grid[x][y] == 'W')) {
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          if (grid[x][y] != 'P') count--;
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          grid[x][y] = 'P';
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          x += dir[0];
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          y += dir[1];
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        }
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      }
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    }
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    return count;
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  }
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}