Compilare: main.cpp: In function 'int bellmanford(int)': main.cpp:34:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < G[u].size() ; j ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:57:29: warning: unused variable 'j' [-Wunused-variable] int m , x , y , z , i , j , ok; ^ main.cpp:57:33: warning: unused variable 'ok' [-Wunused-variable] int m , x , y , z , i , j , ok; ^~ main.cpp:55:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.in" , "r" , stdin); ^ main.cpp:56:46: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.out" , "w" , stdout); ^ main.cpp:58:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &n , &m); ^ main.cpp:61:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d" , &x , &y , &z); ^