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| class Solution {
public String addStrings(String num1, String num2) {
int len1 = num1.length(), len2 = num2.length();
int i1 = len1 - 1, i2 = len2 - 1;
char[] s1 = num1.toCharArray();
char[] s2 = num2.toCharArray();
StringBuilder ans = new StringBuilder();
int cin = 0;
while (i1 >= 0 || i2 >= 0 || cin == 1) {
int n1 = 0, n2 = 0, sum = 0;
if (i1 >= 0) {
n1 = s1[i1] - '0';
i1--;
}
if (i2 >= 0) {
n2 = s2[i2] - '0';
i2--;
}
sum = n1 + n2 + cin;
cin = 0;
if (sum >= 10) {
sum -= 10;
cin = 1;
}
ans.append(sum);
}
return ans.reverse().toString();
}
}
|
