https://leetcode.com/problems/add-strings/description/
题目
Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2.
Note:
- The length of both
num1andnum2is < 5100. - Both
num1andnum2contains only digits0-9. - Both
num1andnum2does not contain any leading zero. - You must not use any built-in BigInteger library or convert the inputs to integer directly.
题目翻译
题目解析
参考答案
#include <iostream>
#include <string>
using namespace std;
class Solution {
public:
string addStrings(string num1, string num2) {
string strResult;
int iFlag = 0;
int iIdx1 = num1.size() - 1;
int iIdx2 = num2.size() - 1;
while (iIdx1 >= 0 && iIdx2 >= 0)
{
int iSum = (num1[iIdx1] - '0') + (num2[iIdx2] - '0') + iFlag;
if (iSum >= 10)
{
iFlag = 1;
iSum -= 10;
}
else
{
iFlag = 0;
}
strResult.append(1, iSum + '0');
iIdx1--;
iIdx2--;
}
while (iIdx1 >= 0)
{
int iSum = (num1[iIdx1] - '0') + iFlag;
if (iSum >= 10)
{
iFlag = 1;
iSum -= 10;
}
else
{
iFlag = 0;
}
strResult.append(1, iSum + '0');
iIdx1--;
}
while (iIdx2 >= 0)
{
int iSum = (num2[iIdx2] - '0') + iFlag;
if (iSum >= 10)
{
iFlag = 1;
iSum -= 10;
}
else
{
iFlag = 0;
}
strResult.append(1, iSum + '0');
iIdx2--;
}
if (iFlag > 0)
{
strResult.append(1, '1');
}
int i = 0;
int j = strResult.size() - 1;
while (i < j)
{
int temp = strResult[i];
strResult[i] = strResult[j];
strResult[j] = temp;
i++;
j--;
}
return strResult;
}
};
int main()
{
string num1 = "1";
string num2 = "9";
Solution o;
string strResult = o.addStrings(num1, num2);
cout << strResult << endl;
return 0;
}
