Compilare: user.cpp: In function ‘void solve()’: user.cpp:20:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j = 1, cost = 0, K = k; ^ user.cpp:20:19: warning: unused variable ‘cost’ [-Wunused-variable] int i, j = 1, cost = 0, K = k; ^ user.cpp:20:29: warning: unused variable ‘K’ [-Wunused-variable] int i, j = 1, cost = 0, K = k; ^ user.cpp: In function ‘void read()’: user.cpp:10:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("metrouri.in", "r", stdin); ^ user.cpp:11:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &m, &k); ^ user.cpp:14:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘void write()’: user.cpp:33:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("metrouri.out", "w", stdout); ^