题解 | #数制转换#

#include <vector>
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
char int_tochar(int num)
{
    char res = 0;
    if (num >= 10)
        res = num - 10 + 'A';
    else res = num + '0';
    return res;
}
int char_toint(char c)
{
    int res = 0;
    if (c >= '0' && c <= '9')
        res = c - '0';
    if (c >= 'A' && c <= 'F')
        res = c - 'A'+10;
    if (c >= 'a' && c <= 'f')
        res = c - 'a'+10;
    return res;
}
void trans(int m, int n, string& s)
{
    string res = "";
    for (int i = 0; i < s.length();)
    {
        int yushu = 0;
        int t;
        for (int j = i; j < s.length(); j++)
        {
            t = yushu;
            yushu = (yushu * m + char_toint(s[j])) % n;
            int tt = (t* m + char_toint(s[j])) / n;
            s[j] = int_tochar(tt);
        }
        res += int_tochar(yushu);
        while (s[i] == '0')
            i++;
    }
    s = res;
}
int main() {
    int a, b;
    string s;
    while (cin >> a)
    {
        cin >> s;
        cin >> b;
        trans(a, b, s);
        reverse(s.begin(), s.end());
        cout << s << endl;
    }
    /*cout<<int_tochar(10);
    cout << char_toint('a');*/
}
// 64 位输出请用 printf("%lld")