6 字符串Z字形变换

//按行分解即可得到相应内容
	//任何显示都可以使用矩阵点来量化
	public String convert(String s, int numRows) {
	    if (numRows == 1) return s;
	    StringBuilder ret = new StringBuilder();
	    int n = s.length();
	    int cycleLen = 2 * numRows - 2;
	    //竖向
	    for (int i = 0; i < numRows; i++) {
	    	//横向
	        for (int j = 0; j + i < n; j += cycleLen) {
	            ret.append(s.charAt(j + i));
	            if (i != 0 && i != numRows - 1 && j + cycleLen - i < n)
	                ret.append(s.charAt(j + cycleLen - i));
	        }
	    }
	    return ret.toString();
	}