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Solutions A simple solution consists in sorting both sequences and running two nested for loops to calculate the possible costs. Although this solution is \(O((n+m) \cdot log(n+m)) + n \cdot m)\), it’s acceptable since the input is small: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 int s, n, m; cin >> s >> n >> m; vector<int> k(n); copy_n(istream_iterator<int>(cin), n, begin(k)); vector<int> u(m); copy_n(istream_iterator<int>(cin), m, begin(u)); sort(begin(k), end(k), greater<>{}); sort(begin(u), end(u), greater<>{}); auto cost = -1; for(auto i : k) { for (auto j : u) { if (i+j<=s) cost = max(cost, i+j); } } cout << cost; Linq-based solution, with cartesian product (by fabrizio_sanmar1): [Read More]

Triple Sum

Solutions Consider this test case: Visually, for each element of B we should mark the elements in A and C that are less than or equal to that element: And, for 3: Performing the operation on the second 3 is redundant, because triplets must be unique. Along the way, we could multiply the count of A’s marked elements with the count of B’s marked elements. All the results will be then accumulated. [Read More]