Compilare: user.cpp: In function ‘void write()’: user.cpp:57:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i<ANS.size(); i++) { ^ user.cpp: In function ‘void read()’: user.cpp:32:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:35:48: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &X[i], &Y[i], &COST[i]); ^