54. 螺旋矩阵

package leetcode;

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

public class demo_54 {
    public List<Integer> spiralOrder(int[][] matrix) {
        List<Integer> list=new ArrayList<Integer>();
        //最外圈的宽度
        int width=matrix[0].length;
        //最外圈的高度
        int height=matrix.length;
        int length=width*height;
        //记录每一次开始的位置
        int start=0;
        int i;
        int j;
        //每一次走完一个完整的外圈
        while(list.size()<length) {
            i=start;
            j=start;
            for(;j<width&&list.size()<length;j++) {
                list.add(matrix[i][j]);
            }
            j=j-1;
            for(i=i+1;i<height&&list.size()<length;i++) {
                list.add(matrix[i][j]);
            }
            i=i-1;
            for(j=j-1;j>=start&&list.size()<length;j--) {
                list.add(matrix[i][j]);
            }
            j=j+1;
            for(i=i-1;i>start&&list.size()<length;i--) {
                list.add(matrix[i][j]);
            }
            start=start+1;
            width=width-1;
            height=height-1;
        }
        for(int num:list) {
            System.out.print(num+" ");
        }
        return list;
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        demo_54 d54=new demo_54();
        int nums[][]= {{1,2,3,4},{5,6,7,8},{9,10,11,12}};
        d54.spiralOrder(nums);
    }

}