[数论] [洛谷] P1017 负进制转换

负进制转换过程与正进制相同

不断取模向下计算

但是负进制在模的过程中会模出负数

若为负数 该步需要特殊操作

ans = mode[a - (a / b + 1) *  b] + ans;

            a = a / b + 1;

#include <iostream>
using namespace std;

typedef long long ll;

int main()
{

    string mode = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    string ans;

    ll a, b;

    cin>>a>>b;

    ll ta = a;

    while(a)
    {
        if(a % b >= 0)
        {
            ans = mode[a % b] + ans;
            
            a /= b;
        }
        else
        {
            ans = mode[a - (a / b + 1) *  b] + ans;

            a = a / b + 1;
        }
    }

    cout<<ta<<'=';

    cout<<ans;

    cout<<"(base"<<b<<")"<<endl;

    return 0;

}