File size: 2,918 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | #include <bits/stdc++.h>
using namespace std;
int N;
int query(int u, int v) {
cout << "? " << u << " " << v << endl;
fflush(stdout);
int d;
cin >> d;
return d;
}
void reconstruct(const vector<int>& S, vector<tuple<int, int, int>>& edges) {
size_t sz = S.size();
if (sz <= 1) return;
if (sz == 2) {
int u = S[0], v = S[1];
int w = query(u, v);
edges.emplace_back(u, v, w);
return;
}
int u0 = S[0];
vector<int> dist_u(N + 1, -1);
int max_d = -1;
int far1 = u0;
for (int v : S) {
if (v == u0) continue;
int d = query(u0, v);
dist_u[v] = d;
if (d > max_d) {
max_d = d;
far1 = v;
}
}
vector<int> dist_f1(N + 1, -1);
dist_f1[far1] = 0;
int max_d2 = -1;
int far2 = far1;
for (int v : S) {
if (v == far1) continue;
int d = query(far1, v);
dist_f1[v] = d;
if (d > max_d2) {
max_d2 = d;
far2 = v;
}
}
int D = max_d2;
vector<int> dist_f2(N + 1, -1);
dist_f2[far2] = 0;
for (int v : S) {
if (v == far2) continue;
int d = query(far2, v);
dist_f2[v] = d;
}
vector<int> path;
for (int x : S) {
int dv = dist_f1[x];
int dw = dist_f2[x];
if (dv + dw == D) {
path.push_back(x);
}
}
sort(path.begin(), path.end(), [&](int a, int b) {
return dist_f1[a] < dist_f1[b];
});
for (size_t i = 0; i + 1 < path.size(); ++i) {
int a = path[i];
int b = path[i + 1];
int w = dist_f1[b] - dist_f1[a];
edges.emplace_back(a, b, w);
}
map<long long, int> pos_to_p;
for (int p : path) {
pos_to_p[dist_f1[p]] = p;
}
vector<vector<int>> subs(path.size());
for (int x : S) {
auto it_path = find(path.begin(), path.end(), x);
if (it_path != path.end()) continue;
long long dvx = dist_f1[x];
long long dwx = dist_f2[x];
long long num = dvx + D - dwx;
if (num % 2 != 0) continue;
long long pos = num / 2;
auto it = pos_to_p.find(pos);
if (it != pos_to_p.end()) {
int att = it->second;
int idx = -1;
for (int j = 0; j < (int)path.size(); ++j) {
if (path[j] == att) {
idx = j;
break;
}
}
if (idx != -1) {
subs[idx].push_back(x);
}
}
}
for (size_t i = 0; i < path.size(); ++i) {
vector<int> subS;
subS.push_back(path[i]);
for (int ss : subs[i]) {
subS.push_back(ss);
}
if (subS.size() > 1) {
reconstruct(subS, edges);
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
int T;
cin >> T;
for (int t = 0; t < T; ++t) {
int n;
cin >> n;
N = n;
vector<int> nodes(n);
for (int i = 0; i < n; ++i) nodes[i] = i + 1;
vector<tuple<int, int, int>> edges;
reconstruct(nodes, edges);
cout << "!";
for (auto [u, v, w] : edges) {
cout << " " << u << " " << v << " " << w;
}
cout << endl;
fflush(stdout);
}
return 0;
} |