https://leetcode.com/problems/add-binary/
模拟加法操作,链表也有类似的问题(Add Two Numbers)。
/*
* author : TK
* date : 2017-02-14
* problem: LeetCode 67: Add Binary
* method : simulate the operation of addition
*/
class Solution {
public:
string addBinary(string a, string b) {
int p1 = a.size() - 1, p2 = b.size() - 1, carry = 0;
// simulate the addition operation
string ret = "";
while (true) {
if (p1 >= 0) carry += (a[p1--] - '0');
if (p2 >= 0) carry += (b[p2--] - '0');
string next_digit = to_string(carry % 2);
carry /= 2;
if (p1 >= 0 || p2 >= 0 || carry != 0 || next_digit != "0") {
ret = next_digit + ret;
} else break;
}
// remove the prefix '0'
int i = 0;
while (i < ret.size()) {
if (ret[i] != '0') break;
i++;
}
if (ret.empty()) ret = "0";
return ret.substr(i, ret.size() - i);
}
};