415. Add Strings
Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2.
Note:
num1 and num2 is < 5100.num1 and num2 contains only digits 0-9.num1 and num2 does not contain any leading zero.java代码:
public class Solution {
public String addStrings(String num1, String num2) {
int len1=num1.length()-1;
int len2=num2.length()-1;
StringBuilder sb=new StringBuilder();
int sum=0,carry=0;
while(len1>=0||len2>=0){
int a=len1>=0?num1.charAt(len1)-‘0‘:0;
int b=len2>=0?num2.charAt(len2)-‘0‘:0;
sum=a+b+carry;
if(sum>9){
sb.insert(0,sum%10);
carry=1;
sum=0;
}else{
sb.insert(0,sum);
sum=0;
carry=0;
}
len1--;
len2--;
}
if(carry==1){
sb.insert(0,1);
}
return sb.toString();
}
}
原文：http://www.cnblogs.com/lcbg/p/6653054.html