题目
描述
Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2.
样例
Given num1 = "123", num2 = "45"
return "168"
解答
思路
注意：
- 从右往左计算
- 作为字符串的结果要转置
代码
代码语言：javascript复制public class Solution {
/**
* @param num1 a non-negative integers
* @param num2 a non-negative integers
* @return return sum of num1 and num2
*/
public String addStrings(String num1, String num2) {
// Write your code here
int carry = 0;
int sum = 0;
char[] c1 = ((num1.length() > num2.length()) ? num1 : num2).toCharArray();
char[] c2 = ((num1.length() > num2.length()) ? num2 : num1).toCharArray();
int l1 = c1.length - 1;
int l2 = c2.length - 1;
StringBuffer sb = new StringBuffer();
for(int i = 0; i < c2.length; i ){
sum = add(c1[l1 - i], c2[l2 - i], carry);
sb.append(sum % 10 "");
carry = sum / 10;
}
for(int j = c2.length; j < c1.length; j ){
sum = add(c1[l1 - j], '0', carry);
sb.append(sum % 10 "");
carry = sum / 10;
}
if(carry == 1){
sb.append(carry "");
}
return sb.reverse().toString();
}
public int add(char a ,char b ,int c){
int q = a - '0';
int p = b - '0';
return q p c;
}
}
