Backspace String Compare

看两个string是不是相同, string里的#号是删除下一个字符.

class Solution {
    public boolean backspaceCompare(String S, String T) {
        StringBuffer sb1 = new StringBuffer(S);
        StringBuffer sb2 = new StringBuffer(T);
        sb1.reverse();
        sb2.reverse();
        return modify(sb1).equals(modify(sb2));
    }
    
    private String modify(StringBuffer sb) {
        int skip = 0;
        StringBuffer tmp = new StringBuffer();
        for(int i = 0 ; i < sb.length(); i++) {
            if(sb.charAt(i) == '#') {
                skip++;
                continue;
            }
            else if(skip > 0){
                skip--;
                continue;
            }
            else{
                   tmp.append(sb.charAt(i));
            }
        }
        System.out.println(tmp.toString());
        return tmp.toString();
    }
}