Leetcode: spiral Matrix II.

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本文详细介绍了如何使用算法生成给定整数n的n×n螺旋矩阵，并提供了相应的代码实现，通过实例演示了从1到n²的元素填充过程。

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Problem:

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 ]
]

Solution:

code

public class Solution {
    public int[][] generateMatrix(int n) {
        int[][] array = new int[n][n];
        int a = 0;
        int b = n - 1;
        int c = 0;
        int d = n - 1;
        int count = 0;
        while (a <= b && c <= d) {
            if (a <= b ) {
                for (int i = c; i <= d; i++) {
                    count++;
                    array[a][i] = count;
                }
                a++;
            }
            if (c <= d) {
                for (int i = a; i <= b; i++) {
                    count++;
                    array[i][d] = count;
                }
                d--;
            }
            if (a <= b) {
                for (int i = d; i >= c; i--) {
                    count++;
                    array[b][i] = count;
                }
                b--;
            }
            if (c <= d) {
                for (int i = b ; i >= a; i--) {
                    count++;
                    array[i][c] = count;
                }
                c++;
            }
        }
        return array;
    }
}