题解 | #大数加法#

import java.util.*;
class Solution {
    public String solve(String num1,String num2){
        StringBuilder s=new StringBuilder();
        int i=num1.length()-1,j=num2.length()-1;int add=0;
        for(;i>=0||j>=0||add!=0;i--,j--)
        {
            int n1=i>=0?num1.charAt(i)-'0':0;
            int n2=j>=0?num2.charAt(j)-'0':0;
            s.append((n1+n2+add)%10);
            add=(n1+n2+add)/10;
        }
        s.reverse();
        return s.toString();
    }
}