1. class Solution {
  2.     public int numEnclaves(int[][] grid) {
  3.         int n = grid.length;
  4.         int m = grid[0].length;
  5.  
  6.         int[][] visited = new int[n][m];
  7.  
  8.         // step-1 check the boundary characters 
  9.         // traversing through boundary 0th col, last row, last col, 0th row
  10.         for(int i=0; i<n; i++)
  11.         {
  12.             for(int j=0; j<m; j++)
  13.             {
  14.                 // 0th col
  15.                 if(grid[i][0] == 1 && visited[i][0] != 1)
  16.                 {
  17.                     dfs(grid, visited, i, 0, n, m);
  18.                 }
  19.                 // last col
  20.                 else if(grid[i][m-1] == 1 && visited[i][m-1] != 1)
  21.                 {
  22.                     dfs(grid, visited, i, m-1, n, m);
  23.                 }
  24.                 // 0th row
  25.                 else if(grid[0][j] == 1 && visited[0][j] != 1)
  26.                 {
  27.                     dfs(grid, visited, 0, j, n, m);
  28.                 }
  29.                 // last row
  30.                 else if(grid[n-1][j] == 1 && visited[n-1][j] != 1)
  31.                 {
  32.                     dfs(grid, visited, n-1, j, n, m);
  33.                 }
  34.             }
  35.         }
  36.  
  37.         int countLandCells = 0;
  38.         for(int i=0; i<n; i++)
  39.         {
  40.             for(int j=0; j<m; j++)
  41.             {
  42.                 if(grid[i][j] == 1)
  43.                     countLandCells++;
  44.  
  45.                 // reverting back as we marked 'Y' for temporary purpose
  46.                 else if(grid[i][j] == 2)
  47.                     grid[i][j] = 1;
  48.             }
  49.         }
  50.         return countLandCells;
  51.     }
  52.  
  53.     int[] deltaRow = {-1, 1, 0, 0};
  54.     int[] deltaCol = {0, 0, 1, -1};
  55.     public void dfs(int[][] grid, int[][] visited, int row, int col, int n, int m)
  56.     {
  57.         visited[row][col] = 1;
  58.         // Mark this cell as visited and temporary number as 2 to prevent it from being changed
  59.         // as these are boundary land cells
  60.         grid[row][col] = 2;
  61.  
  62.         for(int i=0; i<4; i++)
  63.         {
  64.             int nRow = row + deltaRow[i];
  65.             int nCol = col + deltaCol[i];
  66.  
  67.             if(nRow >= 0 && nCol >= 0 && nRow < n && nCol < m)
  68.             {
  69.                 // checking if neighbour cell is land cell
  70.                 if(visited[nRow][nCol] == 0 && grid[nRow][nCol] == 1)
  71.                 {
  72.                     dfs(grid, visited, nRow, nCol, n, m);
  73.                 }
  74.             }
  75.         }
  76.     }
  77. }