class Test54 {
    class Solution {
        fun spiralOrder(matrix: Array<IntArray>): List<Int> {
            val column = matrix[0].size
            val row = matrix.size
            val result = MutableList(column * row) { 0 }

            var read = 0
            var i = 0
            var j = 0
            var direction = 0 // →0 ↓1 ←2 ↑3
            var round = 0

            while (read != column * row){
                result[read] = matrix[i][j]
                read++

                // check boundary
                if ((direction == 0 || direction == 1 ) && j + 1 + round == column){ // at rightmost
                    if (i - round == 0){ //right up
                        direction = 1
                    }
                    if (i + 1 + round == row){
                        direction = 2
                    }
                } else if ((direction == 2 || direction == 3 ) &&j - round == 0){ // left
                    if (i + 1 + round == row){
                        direction = 3
                    }
                    if (i - round -1 == 0){
                        direction = 0
                        round ++
                    }
                }

                // move pointer
                when (direction){
                    0 -> j++
                    1 -> i++
                    2 -> j--
                    3 -> i--
                }
            }

            return result
        }
    }
    fun test(){
        val solution = Solution()
        println(solution.spiralOrder(arrayOf(intArrayOf(1,2,3), intArrayOf(4,5,6), intArrayOf(7,8,9))))
        println(solution.spiralOrder(arrayOf(intArrayOf(1,2,3,4), intArrayOf(5,6,7,8), intArrayOf(9,10,11,12))))

    }
}