File size: 2,628 Bytes
1fd0050 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 | #include <iostream>
#include <vector>
#include <numeric>
#include <algorithm>
#include <map>
#include <tuple>
using namespace std;
map<pair<int, int>, long long> memo;
long long query(int u, int v) {
if (u == v) return 0;
if (u > v) swap(u, v);
if (memo.count({u, v})) {
return memo[{u, v}];
}
cout << "? " << u << " " << v << endl;
long long d;
cin >> d;
return memo[{u, v}] = d;
}
void solve() {
int n;
cin >> n;
memo.clear();
if (n == 1) {
cout << "!" << endl;
return;
}
vector<tuple<int, int, long long>> edges;
vector<vector<pair<int, long long>>> adj(n + 1);
auto add_edge = [&](int u, int v, long long w) {
edges.emplace_back(u, v, w);
adj[u].push_back({v, w});
adj[v].push_back({u, w});
};
if (n == 2) {
long long d = query(1, 2);
cout << "! 1 2 " << d << endl;
return;
}
int A = 1, B = 2;
long long D = query(1, 2);
add_edge(1, 2, D);
vector<int> p_path(n + 1);
vector<long long> dists(n + 1);
for (int i = 3; i <= n; ++i) {
long long dist_Ai = query(A, i);
long long dist_Bi = query(B, i);
long long dist_A_p = (D + dist_Ai - dist_Bi) / 2;
fill(p_path.begin(), p_path.end(), 0);
fill(dists.begin(), dists.end(), -1);
vector<int> q;
q.reserve(i);
q.push_back(A);
dists[A] = 0;
p_path[A] = 0;
int head = 0;
while(head < q.size()){
int u = q[head++];
for(auto& edge : adj[u]){
int v = edge.first;
long long w = edge.second;
if(v != p_path[u]){
p_path[v] = u;
dists[v] = dists[u] + w;
q.push_back(v);
}
}
}
int curr = B;
while(dists[curr] > dist_A_p) {
curr = p_path[curr];
}
int p = curr;
add_edge(p, i, dist_Ai - dist_A_p);
if (dist_Ai > D) {
B = i;
D = dist_Ai;
} else if (dist_Bi > D) {
A = i;
D = dist_Bi;
}
}
cout << "! ";
for (size_t i = 0; i < edges.size(); ++i) {
cout << get<0>(edges[i]) << " " << get<1>(edges[i]) << " " << get<2>(edges[i]) << (i == edges.size() - 1 ? "" : " ");
}
cout << endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.flush();
int t;
cin >> t;
while (t--) {
solve();
}
return 0;
} |