题解 | #数制转换#

#define _CRT_SECURE_NO_WARNINGS 1
#include <bits/stdc++.h>
using namespace std;

int CharToInt(char c) {
    int temp = 0;
    if (c <= '9' && c >= '0')temp = c - '0';
    else temp = c - 'A' + 10;
    return temp;
}
char IntToChar(int temp) {
    char c = ' ';
    if (temp < 10)c = temp + '0';
    else c = temp - 10 + 'A';
    return c;
}

int main() {
    int m = 0, n = 0;
    string str;
    while (cin >> m >> str >> n) {
        vector<char>ansever;
        long long number = 0;
        for (int i = 0; i < str.size(); i++) {
            number = number * m;
            number = number + CharToInt(str[i]);
        }
        while (number != 0) {
            ansever.push_back(IntToChar(number % n));
            number = number / n;
        }
        for (int i = ansever.size() - 1; i >= 0; i--) {
            cout << ansever[i];
        }
    }
    cout << endl;

    return 0;
}