public class BackspaceStringCompare {

public boolean backspaceCompare(String S, String T) {

int i = S.length() - 1, j = T.length() - 1;

int ii = 0, jj = 0;

while(i >= 0 || j >= 0){

if(i >= 0 && S.charAt(i) == '#'){

ii++; i--; continue;

}

if(j >= 0 && T.charAt(j) == '#'){

jj++; j--; continue;

}

if(i >= 0 && ii > 0){

ii--; i--; continue;

}

if(j >= 0 && jj > 0){

jj--; j--; continue;

}

if(i >= 0 && j >= 0 && S.charAt(i) != T.charAt(j)) return false;

else if((i < 0 && j >= 0) || (i >= 0 && j < 0)) return false;

i--; j--;

}

return true;

}

public static void main(String[] args) {

BackspaceStringCompare backspaceStringCompare = new BackspaceStringCompare();

System.out.println(backspaceStringCompare.backspaceCompare("ab#c", "ad#c"));

System.out.println(backspaceStringCompare.backspaceCompare("ab##", "c#d#"));

System.out.println(backspaceStringCompare.backspaceCompare("a##c", "#a#c"));

System.out.println(backspaceStringCompare.backspaceCompare("a#c", "b"));

System.out.println(backspaceStringCompare.backspaceCompare("###", "b"));

System.out.println(backspaceStringCompare.backspaceCompare("###", "###########"));

System.out.println(backspaceStringCompare.backspaceCompare("##a#######", "a#"));

System.out.println(backspaceStringCompare.backspaceCompare("##a#####a##", "a#"));

System.out.println(backspaceStringCompare.backspaceCompare("a##a#####a##", "a#a"));

System.out.println(backspaceStringCompare.backspaceCompare("", ""));

}

}