自己写的一个螺旋矩阵的算法

<script type="text/javascript">
	function Direction(x, y) {
		this.x = x;
		this.y = y;
	}
	
	function generateMatrix(n) {
		var dim = Math.ceil(Math.sqrt(n));
		//var dim = n;
		var cen = Math.ceil(dim / 2) - 1;
		var arr = new Array();
		
		for (var i = 0; i < dim; i++) {
			arr[i] = new Array();
			for(var j = 0; j < dim; j++)
				arr[i][j] = 0;
		}
		
		var dirs = [];
		dirs[0] = new Direction(0, 1);
		dirs[1] = new Direction(1, 0);
		dirs[2] = new Direction(0, -1);
		dirs[3] = new Direction(-1, 0);
	
		var posX = cen;
		var posY = cen;
		arr[posX][posY] = 1;			
		var k = 1;
		var dirIdx = 0;
		var step = 1;
		while (k < n) {			
			for (var i = 0; i < 2; i++) {
				for (var j = 0; j < step; j++) {
					k++;
					if (k > n)
						break;
					var curDir = (dirIdx) % 4;
					arr[posX += dirs[curDir].x][posY += dirs[curDir].y] = k;	
				}
				dirIdx++;
			}
			step++;
			
		}
		
		document.write('<table>');
		for (var i = 0; i < dim; i++) {
			document.write("<tr>");
			for(var j = 0; j < dim; j++) {
			document.write("<td>");
				if (arr[i][j] == 0)
					document.write('*');
				else if (arr[i][j] < 10)
					document.write(" " + arr[i][j]);
				else
					document.write(arr[i][j]);
			document.write("</td>");
			}
			document.write("</tr>");
		}
		
		document.write('<table>');				
	}
	
	generateMatrix(25);
</script>