#include #include #include #include #include #include #include using namespace std; // Precompute perfect squares up to the maximum possible sum (~800) bool is_sq[200005]; int main() { // Optimize input/output operations ios_base::sync_with_stdio(false); cin.tie(NULL); for (int i = 1; i * i < 200005; ++i) { is_sq[i * i] = true; } int N; if (!(cin >> N)) return 0; // Base Case if (N == 2) { cout << 1 << "\n"; cout << 1 << " " << 2 << " " << 1 << "\n"; cout << 1 << " " << 1 << "\n"; return 0; } int M = 2 * N - 3; vector vals(200); iota(vals.begin(), vals.end(), 1); // Fill with available weights 1 to 200 mt19937 rng(1337); shuffle(vals.begin(), vals.end(), rng); int W = vals[0]; vector X(N + 1), Y(N + 1); for (int i = 3; i <= N; ++i) { X[i] = vals[2 * i - 5]; Y[i] = vals[2 * i - 4]; } // Calculates how many pairs of vertices DO NOT have a square-sum path auto get_score = [&]() { int bad = 0; bool ok; // Check paths between 1 and 2 ok = is_sq[W]; if (!ok) { for (int k = 3; k <= N; ++k) { if (is_sq[X[k] + Y[k]]) { ok = true; break; } } } if (!ok) bad++; // Check paths between 1 and v for (int v = 3; v <= N; ++v) { ok = is_sq[X[v]] || is_sq[W + Y[v]]; if (!ok) { for (int k = 3; k <= N; ++k) { if (k == v) continue; if (is_sq[X[k] + Y[k] + Y[v]]) { ok = true; break; } } } if (!ok) bad++; } // Check paths between 2 and v for (int v = 3; v <= N; ++v) { ok = is_sq[Y[v]] || is_sq[W + X[v]]; if (!ok) { for (int k = 3; k <= N; ++k) { if (k == v) continue; if (is_sq[Y[k] + X[k] + X[v]]) { ok = true; break; } } } if (!ok) bad++; } // Check paths between leaf u and leaf v for (int u = 3; u <= N; ++u) { for (int v = u + 1; v <= N; ++v) { ok = is_sq[X[u] + X[v]] || is_sq[Y[u] + Y[v]] || is_sq[X[u] + W + Y[v]] || is_sq[Y[u] + W + X[v]]; if (!ok) { for (int k = 3; k <= N; ++k) { if (k == u || k == v) continue; if (is_sq[X[u] + X[k] + Y[k] + Y[v]] || is_sq[Y[u] + Y[k] + X[k] + X[v]]) { ok = true; break; } } } if (!ok) bad++; } } return bad; }; int best_score = get_score(); auto start_time = chrono::steady_clock::now(); int iters = 0; // Hill Climbing while (best_score > 0) { auto now = chrono::steady_clock::now(); if (chrono::duration(now - start_time).count() > 1.8) break; int type = rng() % 2; int idx1 = rng() % M; int idx2 = (type == 0) ? (rng() % M) : (M + (rng() % (200 - M))); swap(vals[idx1], vals[idx2]); W = vals[0]; for (int i = 3; i <= N; ++i) { X[i] = vals[2 * i - 5]; Y[i] = vals[2 * i - 4]; } int new_score = get_score(); if (new_score <= best_score) { best_score = new_score; } else { // Rollback if the new state is worse swap(vals[idx1], vals[idx2]); W = vals[0]; for (int i = 3; i <= N; ++i) { X[i] = vals[2 * i - 5]; Y[i] = vals[2 * i - 4]; } } // Perform a complete reset if caught in a local minima iters++; if (iters % 3000 == 0 && best_score > 0) { shuffle(vals.begin(), vals.end(), rng); W = vals[0]; for (int i = 3; i <= N; ++i) { X[i] = vals[2 * i - 5]; Y[i] = vals[2 * i - 4]; } best_score = get_score(); } } // --- Output Geometry & Edge Weights --- cout << M << "\n"; cout << "1 2 " << W << "\n"; for (int i = 3; i <= N; ++i) { cout << "1 " << i << " " << X[i] << "\n"; cout << "2 " << i << " " << Y[i] << "\n"; } // Helper lambda to print array paths auto print_path = [&](const vector& p) { cout << p.size(); for (int e : p) cout << " " << e; cout << "\n"; }; // --- Retrieve paths mapped chronologically --- for (int u = 1; u <= N; ++u) { for (int v = u + 1; v <= N; ++v) { if (u == 1 && v == 2) { if (is_sq[W]) { print_path({1}); continue; } bool found = false; for (int k = 3; k <= N; ++k) { if (is_sq[X[k] + Y[k]]) { print_path({2*k-4, 2*k-3}); found = true; break; } } if (!found) print_path({1}); continue; } if (u == 1) { if (is_sq[X[v]]) { print_path({2*v-4}); continue; } if (is_sq[W + Y[v]]) { print_path({1, 2*v-3}); continue; } bool found = false; for (int k = 3; k <= N; ++k) { if (k == v) continue; if (is_sq[X[k] + Y[k] + Y[v]]) { print_path({2*k-4, 2*k-3, 2*v-3}); found = true; break; } } if (!found) print_path({2*v-4}); continue; } if (u == 2) { if (is_sq[Y[v]]) { print_path({2*v-3}); continue; } if (is_sq[W + X[v]]) { print_path({1, 2*v-4}); continue; } bool found = false; for (int k = 3; k <= N; ++k) { if (k == v) continue; if (is_sq[Y[k] + X[k] + X[v]]) { print_path({2*k-3, 2*k-4, 2*v-4}); found = true; break; } } if (!found) print_path({2*v-3}); continue; } // u >= 3 and v >= 3 if (is_sq[X[u] + X[v]]) { print_path({2*u-4, 2*v-4}); continue; } if (is_sq[Y[u] + Y[v]]) { print_path({2*u-3, 2*v-3}); continue; } if (is_sq[X[u] + W + Y[v]]) { print_path({2*u-4, 1, 2*v-3}); continue; } if (is_sq[Y[u] + W + X[v]]) { print_path({2*u-3, 1, 2*v-4}); continue; } bool found = false; for (int k = 3; k <= N; ++k) { if (k == u || k == v) continue; if (is_sq[X[u] + X[k] + Y[k] + Y[v]]) { print_path({2*u-4, 2*k-4, 2*k-3, 2*v-3}); found = true; break; } if (is_sq[Y[u] + Y[k] + X[k] + X[v]]) { print_path({2*u-3, 2*k-3, 2*k-4, 2*v-4}); found = true; break; } } if (!found) print_path({2*u-4, 2*v-4}); } } return 0; }