Leetcode67. 二进制求和

题目传送地址: ​​https://leetcode.cn/problems/add-binary/​​

运行效率

代码如下：

class Solution {
    public static String addBinary(String a, String b) {
        StringBuilder res = new StringBuilder();
        int left = a.length() - 1;
        int right = b.length() - 1;
        int carry = 0;// 进位
        while ((left >= 0 && right >= 0) || carry == 1) {
            int i = 0;
            if (left >= 0) {
                i = a.charAt(left) - '0';
            }
            int i1 = 0;
            if (right >= 0) {
                i1 = b.charAt(right) - '0';
            }
            int sum = i + i1 + carry;
            if (sum >= 2) {
                carry = 1;
            } else {
                carry = 0;
            }
            res.insert(0, sum % 2);
            left--;
            right--;
        }
        if (left >= 0) {
            String substring = a.substring(0, left + 1);
            res.insert(0, substring);
        }
        if (right >= 0) {
            String substring = b.substring(0, right + 1);
            res.insert(0, substring);
        }
        return res.toString();
    }
}