Add Binary
Given two binary strings, return their sum (also a binary string).
For example,
a = "11"
b = "1"
Return "100"
.
解題思路:
題意為兩個字符串表示的二進制相加,求結果。記住常字符串與字符串變量能夠相加,但是字符串不能與數字相加,字符不能與字符串相加。
class Solution { public: string addBinary(string a, string b) { int len1=a.length(); int len2=b.length(); int carry=0; string result=""; int i=len1-1, j=len2-1; while(i>=0&&j>=0){ int r = (a[i]-'0') + (b[j]-'0') + carry; result = (r%2==0 ? "0": "1") + result; carry = r/2; i--; j--; } while(i>=0){ int r = (a[i]-'0') + carry; result = (r%2==0 ? "0": "1") + result; carry = r/2; i--; } while(j>=0){ int r = (b[j]-'0') + carry; result = (r%2==0 ? "0": "1") + result; carry = r/2; j--; } if(carry>0){ result = "1" + result; } return result; } };