Compilare: user.cpp: In function ‘void runBC(std::pair<int, int>)’: user.cpp:30:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < bc.size() ; ++i) ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:42:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[act].size() ; ++i) ^ user.cpp: In function ‘void solve(int, int)’: user.cpp:63:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < T[act].size() ; ++i) ^ user.cpp:76:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < T[act].size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:95:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lianyu.in" , "r" , stdin); ^ user.cpp:96:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lianyu.out" , "w" , stdout); ^ user.cpp:98:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^ user.cpp:99:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &m); ^ user.cpp:100:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &K); ^ user.cpp:103:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &a[i]); ^ user.cpp:107:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &x); ^ user.cpp:108:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &y); ^