59. Spiral Matrix II

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 ]
]

输出n阶旋转矩阵。程序如下所示：
class Solution {
public int[][] generateMatrix(int n) {
int[][] matrix = new int

;
int rowMin = 0, rowMax = n, colMin = 0, colMax = n;
int val = 1;
while (rowMin < rowMax&&colMin < colMax){
for (int i = colMin; i < colMax; ++ i){
matrix[colMin][i] = val ++;
}
for (int i = rowMin + 1; colMax - colMin > 1&&i < rowMax; ++ i){
matrix[i][colMax-1] = val ++;
}
for (int i = colMax - 2; rowMax - rowMin > 1&&i >= colMin; -- i){
matrix[rowMax-1][i] = val ++;
}
for (int i = rowMax - 2; colMax - colMin > 1&&i > rowMin; -- i){
matrix[i][colMin] = val ++;
}
rowMin ++;
rowMax --;
colMin ++;
colMax --;
}
return matrix;
}
}