最短代码（AC）

#include<stdio.h>
int main(){printf("C");}

还有谁？？？

#include<iostream>
#include<fstream>
#include<iomanip>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<string>
//#pragma GCC optimize(2)//O2优化
//#pragma GCC optimize(3)//O3优化
//f6停止程序
#define LL long long
using namespace std;
const int N=1e5+10;
const int Inf=0x3f3f3f3f;
LL a,b,c,d[N]; 
int main(){
// 	freopen("xxx.in","r",stdin);
//	freopen("xxx.out","w",stdout);
	cout<<"A";
	return 0;
}

#include<iostream using namespace std; int main() { return 0; }

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
	cout << "C";
	return 0;
}