C# 代码

public class Solution {
    public int[][] GenerateMatrix(int n) {
        int[][] result = new int[n][];
        for (int a = 0; a < n; a++){
            result[a] = new int[n];
        }
        bool[,] used = new bool[n, n];
        int[] dx = new int[4]{0, 1, 0, -1}, dy = new int[4]{1, 0, -1, 0};
        int d = 0, i = 0, j = 0;
        for (int k = 1; k <= n * n; k++){
            result[i][j] = k;
            used[i, j] = true;
            int x = i + dx[d], y = j + dy[d];
            if (x < 0 || x >= n || y < 0 || y >= n || used[x, y]){
                d = (d + 1) % 4;
                x = i + dx[d];
                y = j + dy[d];
            }

            i = x;
            j = y;
        }

        return result;
    }
}