题解 | 进制转换

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

int main() {
    string s;
    cin>>s;
    int bit = 0;
    int num = 0;
    int length = s.size();
    for(int i = length - 1; i>1; i--){
        if(s[i] >= '0' && s[i] <= '9'){
            num += (s[i] - '0') * pow(16, bit);
            bit++;
        }else if(s[i] >= 'A' && s[i] <= 'F'){
            num +=(s[i] - 'A' + 10) * pow(16, bit);
            bit++;
        }   
    }
    cout<<num;
        
    
}
// 64 位输出请用 printf("%lld")