题解 | 进制转换

#include <iostream>
#include <cmath>
using namespace std;



// 64 位输出请用 printf("%lld")
int suan(int data){
    int result = 1;
    for (int i = 0;i<data; i++) {
        result *= 16;
    }
    return result;
}
int main() {
    string data;
    cin>>data;
    string result = "";
    for(int i = 2;i < data.size();i++){
        result += data[i];
    } 
    int sum = 0;
    int index = 0;
    for(int k =result.size()-1;k>=0;k--){
        if(result[k]>='A'&&result[k]<='F'){
            sum += (result[k]-'A'+10)*suan(index);
        }
        else{
            sum+=(result[k]-'0')*suan(index);
        }
        index++;
    }
    cout<<sum<<endl;
}