04
05/2015
[LeetCode] Add Binary
Add Binary
Given two binary strings, return their sum (also a binary string).
For example,
a = "11"
b = "1"
Return "100".
解题思路：
题意为两个字符串表示的二进制相加，求结果。记住常字符串与字符串变量能够相加，但是字符串不能与数字相加，字符不能与字符串相加。
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;
}
};二次刷题（2015-08-03）
class Solution {
public:
string addBinary(string a, string b) {
string result = "";
int len1=a.length();
int len2=b.length();
int carry = 0;
int i = 1;
while(i<=len1&&i<=len2){
int add = (a[len1 - i] - '0') + (b[len2 - i] - '0') + carry;
carry = add / 2;
result = std::to_string(add % 2) + result;
i++;
}
while(i<=len1){
int add = (a[len1 - i] - '0') + carry;
carry = add / 2;
result = std::to_string(add % 2) + result;
i++;
}
while(i<=len2){
int add = (b[len2 - i] - '0') + carry;
carry = add / 2;
result = std::to_string(add % 2) + result;
i++;
}
if(carry!=0){
result = std::to_string(carry) + result;
}
return result;
}
};转载请注明：康瑞部落 » [LeetCode] Add Binary
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