Given two binary strings, return their sum (also a binary string).
For example,
a = "11"
b = "1"
Return "100".
很简单的题，代码写麻烦了。注意string加的顺序。
class Solution {
public:
string addBinary(string a, string b) {
int la = a.length()-1;
int lb = b.length()-1;
string re;
int flag = 0;
while(la >= 0 && lb >= 0)
{
if(a[la] == '1' && b[lb] == '1')
{
if(flag == 1)
re = "1" + re;
else
re = "0" + re;
flag = 1;
la--;
lb--;
continue;
}
if(a[la] == '1' || b[lb] == '1')
{
if(flag == 1)
{
re = "0" + re;
flag = 1;
}
else
{
re = "1" + re;
flag = 0;
}
la--;
lb--;
continue;
}
if(a[la] == '0' || b[lb] == '0')
{
if(flag==0) re = "0"+re;
else re = "1" +re;
flag=0;
la--;
lb--;
continue;
}
}
while(la >=0)
{
if(a[la] == '1' && flag == 1)
{
re = "0" +re;
}
else if(a[la] == '0' && flag == 0)
{
re = "0" +re;
flag = 0;
}
else {re ="1" +re;flag = 0;}
la--;
}
while(lb >=0)
{
if(b[lb] == '1' && flag == 1)
{
re = "0" +re;
}
else if(b[lb] == '0' && flag == 0)
{
re = "0" +re;
flag = 0;
}
else {re ="1" +re;flag = 0;}
lb--;
}
if(flag == 1) re = "1"+re;
return re;
}
};