LeetCode OJ 59. Spiral Matrix II

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 ]

]

【题目分析】

与Spiral Matrix不同，这个题目要求生成一个方阵，方阵的值是螺旋递增的。

【思路】

其实这个题目与上一个大同小异，他们遍历矩阵的顺序是相同的，只要把取值变为赋值就可以了。

【java代码】

 public class Solution {

     public int[][] generateMatrix(int n) {

         int[][] matrix = new int[n][n];

         int top = 0;

         int bottom = n-1;

         int left = 0;

         int right = n-1;

         int num = 1;

         while(true){

             for(int i = left; i <= right; i++) matrix[top][i] = num++;

             top++;

             if(left > right || top > bottom) break;

             for(int i = top; i <= bottom; i++) matrix[i][right] = num++;

             right--;

             if(left > right || top > bottom) break;

             for(int i = right; i >= left; i--) matrix[bottom][i] = num++;

             bottom--;

             if(left > right || top > bottom) break;

             for(int i = bottom; i >= top; i--) matrix[i][left] = num++;

             left++;

             if(left > right || top > bottom) break;

         }

         return matrix;

     }

 }

巴特西

LeetCode OJ 59. Spiral Matrix II

最新文章

热门文章