题目:
Given two binary strings, return their sum (also a binary string).
For example,
a = "11"
b = "1"
Return "100"
.
解答:
char* addBinary(char* a, char* b) {
int flag = 0;
int tempa, tempb;
int lena = strlen(a);
int lenb = strlen(b);
int max = (lena>lenb) ? lena : lenb;
char* sum;
sum = (char*)malloc(1+max*sizeof(char));
for (int i = 0; i<lena || i<lenb; i++)
{
tempa = (i<lena) ? a[lena-1-i ] - '0' : 0;
tempb = (i < lenb) ? b[lenb -1-i] - '0' : 0;
sum[i] = (tempa + tempb + flag) % 2 + '0';
flag = (tempa + tempb + flag) / 2;
}
if (flag == 1)
{
sum = (char*)realloc(sum, 2 + max*sizeof(char));
max = max + 1;
sum[max-1] = '1';
}
else
{
max = max;
}
for (int i = 0; i<max / 2; i++)
{
int tem;
tem = sum[i];
sum[i] = sum[max -1- i];
sum[max -1-i] = tem;
}
sum[max] = '\0';
return sum;
}