Spiral Matrix II 解答

Question

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

For example,
Given n = 3,

You should return the following matrix:

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

Solution

Similar with Spiral Matrix.

 public class Solution {
     public int[][] generateMatrix(int n) {
         int[][] result = new int[n][n];
         int start = 1, x = 0, y = 0;
         int m = n;
         while (m > 0) {
             if (m == 1) {
                 result[x][y] = start;
                 break;
             }
             for (int i = 0; i < m - 1; i++)
                 result[x][y++] = start++;
             for (int i = 0; i < m - 1; i++)
                 result[x++][y] = start++;
             for (int i = 0; i < m - 1; i++)
                 result[x][y--] = start++;
             for (int i = 0; i < m - 1; i++)
                 result[x--][y] = start++;
             x++;
             y++;
             m -= 2;
         }
         return result;
     }
 }