题解 | #进制转换2#

#include<iostream>
#include<cstdio>
#include<string>
#include<vector>

using namespace std;

char IntToChar(int x){   //数字转字符
    if(x<10){
        return x+'0';
    }else{
        return x-10+'a';
    }
}

int CharToInt(char c){   //字符转数字
    if(c>='0'&&c<='9'){
        return c-'0';
    }else{
        return c-'A'+10;
    }
}


int main()
{
    int m,n;
    cin>>m>>n;
    string str;
    cin >> str;
    long long number=0;
    for(int i=0;i<str.size();++i){     //m进制转十进制
        number*=m;
        number+=CharToInt(str[i]);
    }
    vector<char>answer;
    while(number!=0){
        answer.push_back(IntToChar(number%n));    //十进制转m进制
        number/=n;
    }
    for(int i=answer.size()-1;i>=0;--i){   //逆序输出
        cout<<answer[i];
    }
    return 0;

}