LeetCode刷题笔记（66，二进制求和，Easy）

class Solution {
    public String addBinary(String a, String b) {
        if(a.length() < b.length()){
            return addBinary(b,a);
        }
        int L = Math.max(a.length(),b.length());
        StringBuilder toolman = new StringBuilder();
        int nafla = 0;
        int j = b.length()-1;
        for(int i=L-1;i>-1;i--){
            if(a.charAt(i) == '1') ++nafla;
            if(j > -1 && b.charAt(j--) == '1'){
                ++nafla;
            }
            if(nafla % 2 == 1){
                toolman.append('1');
            }else{
                toolman.append('0');
            }
            nafla /= 2;
        }
        if(nafla == 1){
            toolman.append('1');
        }
        toolman.reverse();
        return toolman.toString();
    }
}