Contest: Codeforces Round 967 (Div. 2) Problem: 2001C - Guess The Tree
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I haven't dealt with this type of problem before, so I don't know what's happening here. Please help me.
here is my code
void solve() {
int n; cin>>n;
vector <int> v[1001];
vector <pair <int,int>> ans;
for(int i=2; i<=n; i++) {
cout << "? " << 1 << ' ' << i << endl;
cout.flush();
int a; cin>>a;
if(a==1) ans.push_back({1, i});
else v[a].push_back(i);
}
for(int i=2; i<=n; i++) {
for(auto j: v[i]) {
cout << "? " << i << ' ' << j << endl;
cout.flush();
int a; cin>>a;
if(a==-1) exit(0);
if(a==i or a==j) ans.push_back({i, j});
else v[a].push_back(j);
}
}
cout << "! ";
for(auto [x,y]: ans) cout << x << ' ' << y << spc;
cout << newl;
cout.flush();
// long_line;
return;
}
and here is my submission