七进制数,模拟计算,求余数 后 reverse即可
C++ 代码
class Solution {
public:
string convertToBase7(int num) {
if(!num) return "0";
bool is_neg = num < 0;
num = abs(num);
string res;
while(num) {
res += to_string(num%7);
num /= 7;
}
reverse(res.begin(), res.end());
if(is_neg) res = "-" + res;
return res;
}
};