Leetcode 67 —— Add Binary

Total Accepted: 78879 Total Submissions: 291470 Difficulty: Easy

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

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

Subscribe to see which companies asked this question

Hide Tags

 Math String

Hide Similar Problems

 (M) Add Two Numbers (M) Multiply Strings (E) Plus One

題意：

計算字符串的加法 返回結果字符串。

思路比較簡單，注意字符串拼接以及進位的判斷。

代碼(已AC 2016-03-24)~

string addBinary(string a, string b) {
	if (a.empty() || b.empty())
	{
		return (a.empty()) ? b : a;
	}

	int inc = 0, posA = a.length() - 1, posB = b.length() - 1, sum = 0;
	string res("");
	while (posA >= 0 && posB >= 0)
	{
		sum = (a[posA] - '0') + (b[posB] - '0') + inc;
		inc = sum / 2;

		res = (char)(sum % 2 + '0') + res;

		posA--, posB--;
	}

	while (posA > -1)
	{
		sum = (a[posA] - '0') + inc;
		inc = sum / 2;

		res = (char)(sum % 2 + '0') + res;
		posA--;
	}

	while (posB > -1)
	{
		sum = (a[posB] - '0') + inc;
		inc = sum / 2;

		res = (char)(sum % 2 + '0') + res;
		posB--;
	}

	if (inc)
		res = (char)(inc + '0') + res;

	return res;
}