Count Sub Islands LeetCode solution in Java

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class Solution {
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  public int countSubIslands(int[][] grid1, int[][] grid2) {
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    int m = grid1.length;
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    int n = grid1[0].length;
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    boolean[][] vis = new boolean[m][n];
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    int count = 0;
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    int[] dir = {1, 0, -1, 0, 1};
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    for (int i = 0; i < m; ++i) {
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      for (int j = 0; j < n; ++j) {
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        if (grid2[i][j] == 0 || vis[i][j]) continue;
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        Queue<int[]> queue = new LinkedList<>();
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        boolean flag = true;
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        vis[i][j] = true;
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        queue.add(new int[] {i, j});
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        while (!queue.isEmpty()) {
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          int[] vtx = queue.remove();
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          if (grid1[vtx[0]][vtx[1]] == 0) flag = false;
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          for (int k = 0; k < 4; ++k) {
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            int x = vtx[0] + dir[k];
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            int y = vtx[1] + dir[k + 1];
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            if (x >= 0 && x < m && y >= 0 && y < n && grid2[x][y] == 1 && !vis[x][y]) {
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              vis[x][y] = true;
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              queue.add(new int[] {x, y});
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            }
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          }
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        }
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        if (flag) ++count;
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      }
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    }
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    return count;
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  }
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}