Compilare: user.cpp: In function ‘int main()’: user.cpp:31:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[nod.front()].size(); i++) ~^~~~~~~~~~~~~~~~~~~~~~ user.cpp:45:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[nod.front()].size(); i++) ~^~~~~~~~~~~~~~~~~~~~~~ user.cpp:17:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("graf.in", "r",stdin); ^ user.cpp:18:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.out", "w",stdout); ^ user.cpp:20:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &x, &y); ^ user.cpp:22:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x1, &y1); ^