LeetCode 504. Base 7

问题描述：

Given an integer, return its base 7 string representation.

Example 1:

Input: 100Output: "202"

Example 2:

Input: -7Output: "-10"

Note: The input will be in range of [-1e7, 1e7].

解题思路：

思路很简单，就像二进制数一样处理，而且本题不涉及负数、补码等问题，简化了难度，只需要判断正负数然后在输出string前面相应的加上正负号即可。

代码：

class Solution {public:    string convertToBase7(int num) {        if(num==0)            return "0";    string res = "";    bool positive = num>0?true:false;    if (!positive)    num = -num;    while (num) {    int y = num % 7;    res = char('0' + y) + res;    num = num / 7;    }        if (!positive)    res = "-" + res;        return res;        }};