Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:16:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < G[u].size() && st[0] == 0 ; j ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:51:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fantasy.in" , "r" , stdin); ^ main.cpp:52:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fantasy.out" , "w" , stdout); ^ main.cpp:54:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &t); ^ main.cpp:57:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d" , &n , &d , &c , &v); ^ main.cpp:60:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &x , &y); ^ main.cpp: In function 'int valid2(int)': main.cpp:45:25: warning: 'nod' may be used uninitialized in this function [-Wmaybe-uninitialized] if(fd[nod] >= fc[nod]) ~~~~~~^ main.cpp: In function 'int main()': main.cpp:45:25: warning: 'nod' may be used uninitialized in this function [-Wmaybe-uninitialized] if(fd[nod] >= fc[nod]) ~~~~~~^ main.cpp:37:21: note: 'nod' was declared here int i , minim , nod; ^~~