首页 > 代码库 > LeetCode 67. Add Binary

LeetCode 67. Add Binary

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

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

这个题目只要注意各种情况你就成功了一大半,特别要注意的是对进位赋值后可能产生的变化,以及最后一位进位为1时,

我们要把这个1插进来。同时注意字符串的低位是我们数值的高位

class Solution {public:    string addBinary(string a, string b) {        reverse(begin(a), end(a));        reverse(begin(b), end(b));        string result;        char num = 0;        int i = 0;        for (;i < a.size() && i < b.size();++i)        {            if (a[i] == 0&&b[i] == 0&&num == 0)            {                result.insert(begin(result), 0);            }            if (a[i] == 1&&b[i] == 1&&num == 1)            {                result.insert(begin(result), 1);            }            if ((a[i] == 0&&b[i] == 1&&num == 1) || (a[i] == 1&&b[i] == 0&&num == 1) ||                (a[i] == 1&&b[i] == 1&&num == 0))            {                result.insert(begin(result), 0);                num = 1;            }            if (a[i] == 1&&b[i] == 0&&num == 0 || a[i] == 0&&b[i] == 1&&num == 0 ||                a[i] == 0&&b[i] == 0&&num == 1)            {                result.insert(begin(result), 1);                num = 0;            }        }        if (i == a.size())        {            for (;i < b.size();++i)            {                if (b[i] == 0&&num == 0)                    result.insert(begin(result), 0);                if (b[i] == 0&&num == 1 || b[i] == 1&&num == 0)                {                    result.insert(begin(result), 1);                    num = 0;                }                if (b[i] == 1&&num == 1)                    result.insert(begin(result), 0);            }        }        else        {            for (;i < a.size();++i)            {                if (a[i] == 0&&num == 0)                    result.insert(begin(result), 0);                if (a[i] == 1&&num == 1)                    result.insert(begin(result), 0);                if (a[i] == 0&&num == 1 || a[i] == 1&&num == 0)                {                    result.insert(begin(result), 1);                    num = 0;                }                            }        }        if (num == 1)result.insert(begin(result), 1);        return result;    }};

 

LeetCode 67. Add Binary