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AddStrings.java
33 lines (26 loc) · 957 Bytes
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AddStrings.java
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// https://leetcode.com/problems/add-strings
class Solution {
public String addStrings(String num1, String num2) {
int maxLen = Math.max(num1.length(), num2.length());
num1 = zeroPad(num1, maxLen);
num2 = zeroPad(num2, maxLen);
//System.out.println(num1);
char[] res = new char[maxLen];
int carry = 0;
for (int i = maxLen - 1; i >= 0; i--) {
char a = num1.charAt(i);
char b = num2.charAt(i);
int sum = (a - 48) + (b - 48) + carry;
res[i] = (char) (sum % 10 + 48);
carry = sum/10;
}
return (carry > 0 ? carry : "") + new String(res);
}
String zeroPad(String num, int targetLen) {
StringBuilder sb = new StringBuilder(num);
while (sb.length() < targetLen) {
sb.insert(0, "0");
}
return sb.toString();
}
}