Submission #1248065

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
/*{{{*/  //template
#define REP(i,n) for(int i=0;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<29
#define LINF LLONG_MAX/3
#define MP make_pair
#define PB push_back
#define pb push_back
#define EB emplace_back
#define ALL(v) (v).begin(),(v).end()
#define all(v) ALL(v)
#define sz(x) (int)(x).size()
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
//struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double{ double d; explicit Double(double x) : d(x){} };
ostream& operator<<(ostream& os,const Double x){ os << fixed << setprecision(20) << x.d; return os; }
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os,const pair<T,U>& p){ os << "(" << p.first << ","<< p.second <<")"; return os; }
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); }
constexpr double eps = 1e-14; 
constexpr ll mod = 1e9+7;
const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1};
/*}}}*/
int N;

void solve(){
    int ans=-1;
    vector<vector<int>> tree(N+10,vector<int>(N+10,0));
    for(int i=2;i<=N;i++){
        cout << "? " << 1 << " " << i << endl;
        int d; cin>>d;
        tree[0][i-1] = tree[i-1][d] = d;
    }

    vector<pii> a;
    for(int i=1;i<N;i++){
        a.pb(make_pair(tree[0][i],i));
    }
    sort(all(a));
    reverse(all(a));

    ans = a[0].first;

    int g = a[0].second;

    for(int i=0;i<N;i++){
        if(i==0 or g==i) continue; 
        cout << "? " << (g+1) <<  " " << (i+1) << endl;
        int d; cin >> d;
        tree[g][i] = tree[i][g] = d;
    }

    for(int i=0;i<N;i++){
        ans = max(ans,tree[g][i]);
    }

    cout << "! " << ans << endl;

    return;
}

int main(){
    cin >> N;
    solve();
    return 0;
}

Submission Info

Judge Result