Add Binary字符数字相加，字符串合成

Given two binary strings, return their sum (also a binary string).

For example,
a = "11"
b = "1"
Return "100".

Hide Tags

Math String

class Solution {
public:
    string addBinary(string a, string b) {
        string longer=a.length()>b.length() ? a:b;
        string shorter=a.length()>b.length() ? b:a;
        int add=;
        int j=longer.length()-;
        for(int i=shorter.length()-;i>=;--i,--j){
            if(shorter[i]-''+longer[j]-''+add>){
                longer[j]=''+(shorter[i]-''+longer[j]-''+add)%;
                add=;
            }else{
                longer[j]=''+(shorter[i]-''+longer[j]-''+add)%;
                add=;
            }
        }
        while(j>=){
            if(longer[j]-''+add>){
                longer[j]='';
                add=;
            }else{
                longer[j]=longer[j]+add;
                add=;
            }
            --j;
        }
        if(add)
            longer.insert(,,'');
        return longer;
    }
};