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 ] ]
public class Solution {
public int[][] generateMatrix(int n) {
int[][] result = new int[n][n];
if(n > 0){
int num = 1;
for(int i = 0; i < n / 2; ++i){
for(int k = i; k < n - i; ++k){
result[i][k] = num;
++num;
}
for(int k = i + 1; k < n - (i + 1); ++k){
result[k][n - (i + 1)] = num;
++num;
}
for(int k = i; k < n - i; ++k){
result[n - 1 - i][n - 1 - k] = num;
++num;
}
for(int k = i + 1; k < n - (i + 1); ++k){
result[n - 1 - k][i] = num;
++num;
}
}
if(n % 2 != 0)
result[n / 2][n / 2] = num;
}
return result;
}
}
leetcode--Spiral Matrix II,布布扣,bubuko.com
原文：http://www.cnblogs.com/averillzheng/p/3790270.html