1 class Solution {
2 public int[] findDiagonalOrder(int[][] matrix) {
3 if(matrix.length == 0) return new int[0];
4 int row = matrix.length;
5 int col = matrix[0].length;
6 int i = 0, j = 0;
7 List<Integer> list = new ArrayList<>();
8 int flag = 1;
9 while(list.size() < row*col){
10 if(i >= 0 && i < row && j >= 0 && j < col){
11 // System.out.println(matrix[i][j]);
12 list.add(matrix[i][j]);
13 if(flag == 1){
14 i = i-1;
15 j = j+1;
16 }else{
17 i = i+1;
18 j = j-1;
19 }
20 }else if(flag == 1){
21 if(j < col){
22 i = i+1;
23 }else{
24 i = i+2;
25 j = j-1;
26
27 }
28 flag = - flag;
29 }else if(flag == -1){
30 if(i >= row){
31 j = j+2;
32 i = i-1;
33 }else{
34 j = j+1;
35 }
36 flag = -flag;
37 }
38 }
39 int[] res = new int[row*col];
40 for(int k = 0; k < res.length; k++){
41 res[k] = list.get(k);
42 }
43 return res;
44 }
45 }
