Find All Groups of Farmland LeetCode solution in Java

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class Solution {
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  int[] arr;
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  public int[][] findFarmland(int[][] land) {
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    List<int[]> res = new ArrayList<>();
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    for (int i = 0; i < land.length; i++)
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      for (int j = 0; j < land[0].length; j++) {
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        if (land[i][j] == 1) {
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          arr = new int[] {i, j, 0, 0};
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          dfs(land, i, j);
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          res.add(arr);
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        }
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      }
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    return res.stream().map(i -> i).toArray(int[][]::new);
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  }
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  public void dfs(int[][] land, int i, int j) {
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    if (i < 0 || j < 0 || i >= land.length || j >= land[0].length || land[i][j] == 0) return;
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    arr[2] = Math.max(i, arr[2]);
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    arr[3] = Math.max(j, arr[3]);
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    land[i][j] = 0;
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    dfs(land, i - 1, j);
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    dfs(land, i, j + 1);
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    dfs(land, i + 1, j);
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    dfs(land, i, j - 1);
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  }
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}