Compilare: main.cpp: In function 'int main()': main.cpp:63:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < G[u].size() ; j ++) ~~^~~~~~~~~~~~~ main.cpp:25:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("padure.in" , "r" , stdin); ^ main.cpp:26:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("padure.out" , "w" , stdout); ^ main.cpp:28:60: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d" , &n , &m , &xs , &ys , &xf , &yf); ^ main.cpp:31:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &a[i][j]); ^