Compilare: user.cpp: In function ‘int dijkstra()’: user.cpp:39:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a[x].size(); ++ i) ^ user.cpp: In function ‘int main()’: user.cpp:73:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a[x].size(); ++ i) ^ user.cpp:54:46: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(F, "%d %d %d %d ", &n, &m, &s, &d); ^ user.cpp:57:50: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(F, "%d %d %d %d ", &x, &y, &c, &z); ^