包不AC

#include<bits/stdc++.h>
using namespace std;
long long s[10000000],ans;
string a;
int main(){
	cin >> a;
	for(int i=0; i<a.size(); i++) {
		if(a[a.size()-i-1]>='A'&&a[a.size()-i-1]<='F') s[i]=a[a.size()-i-1]-'A'+10;
		else s[i]=a[a.size()-i-1]-'0';
	}
	for(int i=0; i<a.size(); i++) {
		ans+=s[i]*pow(16,i);
	}
	cout << ans;
	return 0;
}

包对AC

#include<queue>
#include<math.h>
#include<stdio.h>
#include<iostream>
#include<vector>
#include<iomanip>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<utility>
#include<cstring>
#include<stack>
#include<fstream>
#include<string>
using namespace std;
typedef long long ll;
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
string s;
long long c , x , ans = 0 , p = 1;
int main()
{
	cin>>s;
	c = s.size() - 1;
	for ( int i = c ; i >= 0 ; i-- )
	{
		if ( s[i] >= '0' && s[i] <= '9' )
		{
			x = s[i] - '0';
		}
		else if ( s[i] >= 'A' && s[i] <= 'Z' )
		{
			x = s[i] - 'A' + 10;
		}
		else 
		{
			x = s[i] - 'a' + 10;
		}
		ans += x * p;
		p *= 16;
	}
	cout << ans;
	return 0;
}

#include #include<bits/stdc++.h> #include <math.h> #include <stdio.h> #include #include <string.h> #include #include<bits/stdc++.h> #include #include #include #include #include #include #include #include <math.h> #include <stdio.h> #include #include <string.h> #include using namespace std; string s; int main(){ cin>>s; long c=s.size()-1,ans=0,p=1; { for(int i=c;i>=0;i--) {

int x;
	if(s[i]>='0'&&s[i]<='9')x=s[i]-'0';
	else if(s[i]>='A'&&s[i]<='Z')x=s[i]-'A'+10;
	else x=s[i]-'a'+10;
	ans+=x*p;
	p*=16;
}	}

cout<<ans; return 0; }