LeetCode | Spiral Matrix II

题目

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 ]
]

分析
和Spiral Matrix一样的思路，但是矩阵是方阵了，代码会更简洁些。

代码

public class SpiralMatrixII {
public int[][] generateMatrix(int n) {
int[][] matrix = new int

;
int min = 0;
int max = n - 1;
int num = 1;
while (min <= max) {
for (int i = min; i <= max; ++i) {
matrix[min][i] = num++;
}
for (int i = min + 1; i <= max; ++i) {
matrix[i][max] = num++;
}
if (min != max) {
for (int i = max - 1; i >= min; --i) {
matrix[max][i] = num++;
}
}
for (int i = max - 1; i > min; --i) {
matrix[i][min] = num++;
}

++min;
++max;
}
return matrix;
}
}