Compilare: main.cpp: In function 'std::vector<int> solve(int, std::vector<int>, std::vector<int>)': main.cpp:126:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[i].size() > mx) {mx = v[i].size(); rad = i;} ~~~~~~~~~~~~^~~~ main.cpp:157:9: warning: unused variable 'last' [-Wunused-variable] int last = 2; ^~~~ main.cpp: In function 'int main()': main.cpp:186:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arborex.in", "r", stdin); ^ main.cpp:187:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arborex.out", "w", stdout); ^ main.cpp:190:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:193:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^