48. 994. Rotting Oranges

class Solution {
    public int orangesRotting(int[][] grid) {
        Queue<int[]>queue = new LinkedList<>();
        int freshOranges=0;
        //we will count the fresh orange and enter data in queue if rotten orange
        int m = grid.length;
        int n = grid[0].length;
        for(int i=0;i<m;i++){
            for(int j=0;j<n;j++){
                if(grid[i][j]==2){
                    queue.offer(new int[]{i,j});
                }else if(grid[i][j]==1){
                    freshOranges++;
                }
            }
        }

        int min = 0;
        //for traversing the up down left right we need a direction array
        int[][] directions = {{-1,0},{1,0},{0,-1},{0,1}};

        //now we traverse the queue untill it is not empry and freshOrabges are changed to rotted
        while(!queue.isEmpty()&& freshOranges>0){
            int size = queue.size();

            for(int i=0;i<size;i++){
                int curr[] = queue.poll(); //current orange position

                //now we traverse if any frsh orange present at left,right,top,bottom
                for(int[] dir:directions){
                    int newRow = curr[0]+dir[0];
                    int newCol = curr[1]+dir[1];
                    //now we check new row and col is valid
                    if((newRow>=0 && newRow<m && newCol>=0 && newCol<n) && grid[newRow][newCol]==1){
                        grid[newRow][newCol]=2;
                        queue.offer(new int[]{newRow,newCol});
                        freshOranges--;
                    }
                }
            }
            min++;
        }
        return freshOranges==0?min:-1;
        
    }
}