Compilare: main.cpp: In function 'int main()': main.cpp:44:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("panza.in", "r", stdin); ^ main.cpp:45:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("panza.out", "w", stdout); ^ main.cpp:47:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &n, &m, &s, &f); ^ main.cpp:49:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (int i = 1; i <= m; i++) scanf("%d", &a[i]); ^ main.cpp:51:67: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (int i = 1; i <= n; i++) scanf("%d %d", &x[i].fst, &x[i].snd); ^