Compilare: user.cpp: In function ‘void GatherWood(int, int, int64)’: user.cpp:46:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < T[x].size(); ++i) { ^ user.cpp:48:9: warning: unused variable ‘l’ [-Wunused-variable] int64 l = T[x][i].second; ^ user.cpp: In function ‘void Dfs(int, int, int64, int64)’: user.cpp:79:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < T[x].size(); ++i) { ^ user.cpp:113:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < sons.size(); ++i) { ^ user.cpp:136:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < sons.size(); ++i) { ^ user.cpp:111:6: warning: unused variable ‘last’ [-Wunused-variable] int last = sons.size() - 1; ^ user.cpp: In function ‘int main()’: user.cpp:166:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invtree.in", "r", stdin); ^ user.cpp:167:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invtree.out", "w", stdout); ^