CodeForces 727C GuessTheArray 第一道交互题

//http://codeforces.com/problemset/problem/727/C
//水 掌握一下交互题格式
#include<bits/stdc++.h>
using namespace std;
const int MAX=1e5+5;
int N,A[MAX];
int main()
{
int S12,S13,S23,temp;
cin>>N;
cout<<"? 1 2\n";
fflush(stdout);
cin>>S12;
cout<<"? 1 3\n";
fflush(stdout);
cin>>S13;
cout<<"? 2 3\n";
fflush(stdout);
cin>>S23;
A[2]=(S12+S23-S13)/2;
A[1]=S12-A[2],A[3]=S23-A[2];
for (int i=4;i<=N;i++)
{
cout<<"? 2 "<<i<<'\n';
fflush(stdout);
cin>>temp;
A[i]=temp-A[2];
}
cout<<"! ";
for (int i=1;i<=N;i++)
cout<<A[i]<<' ';
return 0;
}