Compilare: user.cpp: In function ‘void BFS()’: user.cpp:52:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < vec[i].size(); k++) { ^ user.cpp: In function ‘void DFS(int)’: user.cpp:108:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (z = 0; z < child[x].size(); z++) { ^ user.cpp: In function ‘int BruteForceConnectivityTest(int, int)’: user.cpp:153:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < vec[i].size(); k++) { ^ user.cpp: In function ‘void ReadTree()’: user.cpp:29:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] } else scanf("%d %d", &i, &j); ^ user.cpp: In function ‘void ProcessOperations()’: user.cpp:187:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &t, &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:216:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disconnect.in", "r", stdin); ^ user.cpp:217:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disconnect.out", "w", stdout); ^ user.cpp:222:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] } else scanf("%d %d", &N, &M); ^