螺旋矩阵

给定一个包含 m x n 个元素的矩阵（m 行, n 列），请按照顺时针螺旋顺序，返回矩阵中的所有元素。
示例 1:

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

示例 2:

输入:  
[  
  [1, 2, 3, 4],  
  [5, 6, 7, 8],  
  [9,10,11,12]  
]  
输出: [1,2,3,4,8,12,11,10,9,5,6,7]  

思路：算出来每个数组有多少圈，然后for循环输出每圈的数字~

package algorithm;

import util.LogUtil;

import java.util.ArrayList;
import java.util.List;

public class SpiralMatrix {

    public void test() {
        List<Integer> list = spiralOrder(initArray(3, 1));
        LogUtil.Companion.d(list.toString());
    }

    private List<Integer> spiralOrder(int[][] matrix) {
        List<Integer> result = new ArrayList<>();
        if (matrix.length == 0) {
            return result;
        }
        //m是行数，n是列数
        int m = matrix.length, n = matrix[0].length;
        int[] sss = new int[m * n];
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[i].length; j++) {
                sss[i * n + j] = matrix[i][j];
            }
        }
        //行或列哪个最小。
        int min = (m < n ? m : n);
        //一共有几层
        int level = (min % 2 == 0 ? min : min + 1) / 2;

        LogUtil.Companion.d("m->" + m + " n->" + n);
        for (int i = 0; i < level; i++) {
            readALevel(result, i, sss, m, n);
        }
        return result;
    }

    private int lastIndex = -1;

    private void readALevel(List<Integer> list, int level, int[] matrix, int m, int n) {
        int x = m - level * 2;//第level圈有几列
        int y = n - level * 2;//第level圈有几行
        int max;//这一个level一共有多少个数。一列减去两个顶点
        if (x == 1 || y == 1) {
            max = x == 1 ? y : x;
        } else {
            max = ((x + y - 2) * 2);
        }
        LogUtil.Companion.d("第" + level + "圈有" + x + "列，有" + y + "行，一共有" + max + "个数字");
        StringBuilder sb = new StringBuilder();
        int index = lastIndex;
        for (int i = 0; i < max; i++) {
            if (i < y) {
                index++;
                sb.append(index).append(" ");
                list.add(matrix[index]);
            } else if (i < x + y - 1) {
                index += n;
                sb.append(index).append(" ");
                list.add(matrix[index]);
            } else if (i < x + 2 * y - 2) {
                index--;
                sb.append(index).append(" ");
                list.add(matrix[index]);
            } else {
                index -= n;
                sb.append(index).append(" ");
                list.add(matrix[index]);
            }
        }
        LogUtil.Companion.d("--------->" + sb.toString());
        lastIndex = index;
    }

    private int[][] initArray(int x, int y) {
        int num = 0;
        StringBuilder sb = new StringBuilder();
        int[][] xy = new int[x][y];
        for (int i = 0; i < x; i++) {
            for (int j = 0; j < y; j++) {
                xy[i][j] = num;
                sb.append(num);
                sb.append((num < 10) ? "  " : " ");
                num++;
            }
            sb.append("\n");
        }
        int min = (x < y ? x : y);
        int level = (min % 2 == 0 ? min : min + 1) / 2;
        sb.append("----------------------->").append(level);
        LogUtil.Companion.d(sb.toString());
        return xy;
    }
}

螺旋矩阵LeetCode直达