Compilare: main.cpp: In function 'int main()': main.cpp:37:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < G[x].size() ; j ++) ~~^~~~~~~~~~~~~ main.cpp:16:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.in" , "r" , stdin); ^ main.cpp:17:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.out" , "w" , stdout); ^ main.cpp:20:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d" , &n , &m); ^ main.cpp:23:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d" , &x , &y , &z); ^