标签：
Given two binary strings, return their sum (also a binary string).
For example,
a = "11"
b = "1"
Return "100".
题解：二进制字符串相加
public String addBinary(String a, String b) {
//c表示为进位的
int len1 = a.length()-1,len2 = b.length()-1,c=0;
StringBuffer sb = new StringBuffer();
while(len1>=0 && len2>=0){
int temp = (a.charAt(len1)-‘0‘)+(b.charAt(len2)-‘0‘)+c;
c = temp/2;
temp = temp%2;
sb.insert(0, temp+"");
len1--;
len2--;
}
while(len1>=0){
int temp = (a.charAt(len1)-‘0‘)+c;
c = temp/2;
temp = temp%2;
sb.insert(0, temp+"");
len1--;
}
while(len2>=0){
int temp = (b.charAt(len2)-‘0‘)+c;
c = temp/2;
temp = temp%2;
sb.insert(0, temp+"");
len2--;
}
//注意1,1的情况要进位
if(c==1)
sb.insert(0,c+"");
return sb.toString();
}
别人的短码：
public String addBinary(String a, String b) {
StringBuilder sb = new StringBuilder();
int carry = 0;
for(int i=a.length()-1,j=b.length()-1;i>=0 || j>=0;i--,j--){
int v1 = (i<0)?0:a.charAt(i)-‘0‘;
int v2 = (j<0)?0:b.charAt(j)-‘0‘;
int val = (v1+v2+carry)%2;
carry = (v1+v2+carry)/2;
sb.insert(0,(char)(val+‘0‘));
}
if(carry == 1) sb.insert(0,‘1‘);
return sb.toString();
}
标签：
原文地址：http://www.cnblogs.com/lzeffort/p/4833712.html
