LeetCode: Add Binary

C++:

class Solution {
public:
    string addBinary(string a, string b) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (a.size() > b.size()) b = string(a.size()-b.size(), '0') + b;
        if (a.size() < b.size()) a = string(b.size()-a.size(), '0') + a;
        for (int i = 0; i < a.size(); i++) a[i] += int(b[i]-'0');
        int carry = 0;
        for (int i = a.size()-1; i >= 0; i--) {
            a[i] += carry;
            carry = (a[i]-'0') / 2;
            if (a[i] > '1') a[i] = '0' + (a[i]-'0') % 2;
        }
        if (carry) a = '1'+a;
        return a;
    }
};

java: 填补短string前面零字符串的操作很烦

public class Solution {
    public String addBinary(String a, String b) {
        int aLen = a.length();
        int bLen = b.length();
        for (int i = 0; i < Math.abs(aLen - bLen); i++)
        {
            if (aLen < bLen)
            {
                a = "0" + a;
            }
            else
            {
                b = "0" + b;
            }
        }
        char[] cs1 = a.toCharArray();
        char[] cs2 = b.toCharArray();
        char[] cs3 = new char[a.length()];
        int c = 0;
        for (int i = a.length()-1; i >= 0; i--)
        {
            int tmp = c + (cs1[i] - '0') + (cs2[i] - '0');
            c = tmp / 2;
            cs3[i] = (char)('0' + tmp % 2);
        }
        String ans = new String(cs3);
        if (c > 0)
        {
            ans = "1" + ans;
        }
        return ans;
    }
}