Compilare: main.cpp: In function 'void read()': main.cpp:16:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &N, &M, &K, &P); ^ main.cpp:24:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ main.cpp: In function 'int main()': main.cpp:33:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ture.in", "r", stdin); ^ main.cpp:34:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ture.out", "w", stdout); ^