994. Rotting Oranges

class Solution {
    func orangesRotting(_ g: [[Int]]) -> Int {
        var queue = [(Int, Int)]()
        var grid = g
        var goodCount = 0
        for i in 0 ..< grid.count {
            for j in 0 ..< grid[0].count{
                if grid[i][j] == 1 {
                    goodCount += 1
                }else if grid[i][j] == 2{
                    queue.append((i,j))
                }
            }
        }

        var day = 0
        let dx = [0, 0, -1, 1]
        let dy = [1, -1 , 0 , 0]
        while goodCount > 0 && queue.count > 0{
            day += 1
            let size = queue.count
            for _ in 0 ..< size{
                let cur = queue.removeFirst()
                for i in 0 ..< 4{
                    let nextX = cur.0 + dx[i]
                    let nextY = cur.1 + dy[i]
                    if nextX >= 0 && nextX < grid.count && nextY >= 0 && nextY < grid[0].count && grid[nextX][nextY] == 1{
                        queue.append((nextX, nextY))
                        grid[nextX][nextY] = 2
                        goodCount -= 1
                    }
                }
            }
        }

        return goodCount == 0 ? day : -1

    }
}