Compilare: main.cpp: In function 'int dijkstra(int, int)': main.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < G[u].size() ; i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:86:25: warning: unused variable 'j' [-Wunused-variable] int m , s , t , i , j , x , y , c , z; ^ main.cpp:84:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.in" , "r" , stdin); ^ main.cpp:85:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.out" , "w" , stdout); ^ main.cpp:87:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d" , &n , &m , &s , &t); ^ main.cpp:90:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d" , &x , &y , &c , &z); ^