leetcode498

public class Solution {
    public int[] FindDiagonalOrder(int[,] matrix) {
        var row = matrix.GetLength();
            var col = matrix.GetLength();

            var upBound = row -  + col - ;

            var ary = new int[row * col];

            int i = ;
            int j = ;

            var index = ;

            if (row == )
            {
                for (int m = ; m < col; m++)
                {
                    ary[index++] = matrix[, m];
                }
                return ary;
            }
            if (col == )
            {
                for (int m = ; m < row; m++)
                {
                    ary[index++] = matrix[m, ];
                }
                return ary;
            }

            var direction = true;//

            for (int k = ; k <= upBound; k++)//对角线上的i，j之和
            {
                if (i ==  && j == )
                {
                    ary[index++] = matrix[i, j];
                    j = ;
                    continue;
                }
                //结束点
                if (i == row -  && j == col - )
                {
                    ary[index++] = matrix[i, j];
                    break;
                }
                var EndJ = Math.Min(i, col - );//
                var EndI = Math.Min(j, row - );//
                while (i + j == k)
                {
                    ary[index++] = matrix[i, j];
                    if ((direction && (j ==  || i == row - )) || (!direction && (i ==  || j == col - )))
                    {
                        if (direction)
                        {
                            i++;
                            if (i > row - )
                            {
                                i = row - ;
                                j++;
                                if (j > col - )
                                {
                                    j = col - ;
                                }
                            }
                        }
                        else
                        {
                            j++;
                            if (j > col - )
                            {
                                j = col - ;
                                i++;
                                if (i > row - )
                                {
                                    i = row - ;
                                }
                            }
                        }

                        direction = !direction;
                        continue;
                    }
                    if (direction)
                    {
                        i++;
                        if (i > row - )
                        {
                            i = row - ;
                        }
                        j--;
                        if (j < )
                        {
                            j = ;
                        }
                    }
                    else
                    {
                        j++;
                        if (j > col - )
                        {
                            j = col - ;
                        }
                        i--;
                        if (i < )
                        {
                            i = ;
                        }
                    }

                }
            }
            return ary;
    }
}

https://leetcode.com/problems/diagonal-traverse/#/description