Compilare: user.cpp: In function ‘bool operator<(const muchie&, const muchie&)’: user.cpp:22:21: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] lhs.x == rhs.x && lhs.y < rhs.y || ^ user.cpp:23:21: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] lhs.y == rhs.y && lhs.cost < rhs.cost; ^ user.cpp: In function ‘int main()’: user.cpp:75:26: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:76:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOU, "w", stdout); ^ user.cpp:78:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:80:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &value); ^