171. Excel 表列序号

package leetcode;

public class demo_171 {
    public int titleToNumber(String columnTitle) {
        int num=0;
        //类似于二进制转化为十进制，这里是26
        for(int i=0;i<columnTitle.length();i++) {
            num=(int)(num+(columnTitle.charAt(i)-64)*Math.pow(26.0, (columnTitle.length()-i-1)));
        }
        System.out.println(num);
        return num;
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        demo_171 d171=new demo_171();
        String columnTitle="FXSHRXW";
        d171.titleToNumber(columnTitle);
    }

}