67. Add Binary

[이벤트(1.226)]

class Solution {

public String addBinary(String a, String b) {

StringBuilder sb = new StringBuilder();

int AIdx = a.length() - 1;

int BIdx = b.length() - 1;

int counter = 0;

while(AIdx >= 0 || BIdx >= 0 || counter == 1) {

int ai = 0, bi = 0;

if(AIdx >= 0) {

ai = a.charAt(AIdx) - '0';

}

if(BIdx >= 0) {

bi = b.charAt(BIdx) - '0';

}

int current = ai + bi + counter;

sb.append(current%2);

counter = current/2;

BIdx--;

AIdx--;

}

return sb.reverse().toString();

}

}