https://leetcode.com/problems/convert-a-number-to-hexadecimal/description/
题目
Given an integer, write an algorithm to convert it to hexadecimal. For negative integer, two’s complement method is used.
Note:
- All letters in hexadecimal (a-f) must be in lowercase.
- The hexadecimal string must not contain extra leading 0s. If the number is zero, it is represented by a single zero character ‘0’; otherwise, the first character in the hexadecimal string will not be the zero character.
- The given number is guaranteed to fit within the range of a 32-bit signed integer.
- You must not use any method provided by the library which converts/formats the number to hex directly.
Example 1:
Input:
26
Output:
"1a"
Example 2:
Input:
-1
Output:
"ffffffff"
题目翻译
题目解析
参考答案
#include <iostream>
#include <string>
using namespace std;
class Solution {
public:
char toChar(unsigned int iNum)
{
if (iNum < 10)
{
return iNum + '0';
}
else
{
return iNum - 10 + 'a';
}
}
string toHex(int num) {
string strRet;
unsigned int uiNum = num;
unsigned int iRemainder = uiNum;
unsigned int iComplement = 0;
while (1)
{
if (iRemainder < 16)
{
strRet.append(1, toChar(iRemainder));
break;
}
else
{
iComplement = iRemainder % 16;
iRemainder = iRemainder / 16;
strRet.append(1, toChar(iComplement));
}
}
int i = 0;
int j = strRet.size() - 1;
while (i < j)
{
int temp = strRet[i];
strRet[i] = strRet[j];
strRet[j] = temp;
i++;
j--;
}
return strRet;
}
};
int main()
{
Solution o;
string strRet = o.toHex(-1);
cout << strRet << endl;
return 0;
}
