#include <vector> #include <unordered_map> #include <algorithm> vector<int> construct_range(int M, int K) { vector<int> mm; mm.push_back(0); return mm; } long long count_triples(std::vector<int> H) { int n = (int)H.size(); std::unordered_map<int, std::vector<int>> groups1; // Build groups1: d_val -> list of k for (int k = 0; k < n; ++k) { int d_val = k - H[k]; if (d_val >= 0) { groups1[d_val].push_back(k); } } // Sort each group's list for (auto &p : groups1) { std::sort(p.second.begin(), p.second.end()); } long long total = 0; // -------- First big loop (corresponds to first Python for-block) -------- for (const auto &p : groups1) { int i = p.first; if (i < 0 || i >= n) continue; const std::vector<int> &L = p.second; auto it = std::upper_bound(L.begin(), L.end(), i); // bisect_right for (; it != L.end(); ++it) { int k = *it; if (k >= n) break; int M = k - i; if (M < 2) continue; int required = M - H[i]; if (required < 1 || required > M - 1) continue; int count_triple = 0; int j1 = i + H[i]; if (j1 < k && j1 < n && H[j1] == required) { count_triple++; } if (required != H[i]) { int j2 = i + required; if (j2 < k && j2 < n && H[j2] == required) { count_triple++; } } total += count_triple; } } // -------- Second big loop -------- for (int i = 0; i < n; ++i) { int M = H[i]; if (M < 2) continue; int k = i + M; if (k >= n) continue; if (H[k] < 1 || H[k] >= M) continue; int required = M - H[k]; int count_triple = 0; int j1 = i + required; if (j1 < k && j1 < n && H[j1] == required) { count_triple++; } if (required != H[k]) { int j2 = i + H[k]; if (j2 != j1 && j2 < k && j2 < n && H[j2] == required) { count_triple++; } } total += count_triple; } // -------- Third big loop -------- for (int i = 0; i < n; ++i) { int d = i + H[i]; if (d < 0 || d >= n) continue; auto it_group = groups1.find(d); if (it_group == groups1.end()) continue; const std::vector<int> &L = it_group->second; auto it = std::upper_bound(L.begin(), L.end(), d); // bisect_right for (; it != L.end(); ++it) { int k = *it; if (k >= n) break; int M = k - i; if (M < 2) continue; int j1 = d; int j2 = k - d + i; int count_triple = 0; if (0 <= j1 && j1 < k && j1 < n && H[j1] == M) { count_triple++; } if (0 <= j2 && j2 < k && j2 < n && j2 != j1 && H[j2] == M) { count_triple++; } total += count_triple; } } return total; }

triples.cpp:5:1: error: 'vector' does not name a type
    5 | vector<int> construct_range(int M, int K) {
      | ^~~~~~