java solution
class Solution {
public String addBinary(String a, String b) {
StringBuilder result = new StringBuilder();
//首先设置2个指针, 从右往左处理
int i = a.length() - 1;
int j = b.length() - 1;
int carry = 0; //设置进位标志位
//从2个字符串的末尾向前遍历
while(i >= 0 || j >= 0 || carry != 0) {
//先分别获取2个字符串当前位置的十进制数值
int digitA