Compilare: main.cpp: In function 'int knapsack_2D(std::vector<int>&, std::vector<int>&, int)': main.cpp:11:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= w.size(); i++) { ~~^~~~~~~~~~~ main.cpp: In function 'int knapsack_2D_opt(std::vector<int>&, std::vector<int>&, int)': main.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < w.size(); i++) { ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:59:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rucsac.in", "r", stdin); ^