LeetCode 59

https://leetcode-cn.com/problems/spiral-matrix-ii/

很简单的一道题，不用解释过多的东西，只要控制好遍历的边界问题就好，心中有数做啥都不怕

class Solution {
    public int[][] generateMatrix(int n) {
        if(n == 0){
            return new int[0][0];
        }
        int[][] res = new int[n][n];
        int max = n*n;
        int count = 1;
        int pos = 0;
//当数填到n的平方的时候结束
        while(count <= max){
//开始填左上到右上的列，pos用于控制每一圈的大小
            for(int i = pos; i <= n-1-pos;i++){
                res[pos][i] = count;
                count++;
            }
//开始填从右上到右下的行
            for (int i = pos+1;i <= n -pos-1;i++){
                res[i][n-pos-1] = count;
                count++;
            }
//开始填右下到坐下的列
            for (int i = n-2-pos;i>=pos;i--){
                res[n-pos-1][i] = count;
                count++;
            }
//开始填左下到左上-1的行
            for (int i = n-2-pos;i > pos;i--){
                res[i][pos] = count;
                count++;
            }
//控制当前的圈数最终填写的地方
            pos++;
        }
        return res;
    }
}