题解 | #进制转换#

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

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