Compilare: main.cpp: In function 'int main()': main.cpp:30:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("flori.in", "r", stdin); ^ main.cpp:31:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("flori.out", "w", stdout); ^ main.cpp:35:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ main.cpp:41:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &head[i]); ^ main.cpp:43:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ main.cpp:37:16: warning: iteration 1003 invokes undefined behavior [-Waggressive-loop-optimizations] arb[i] = i; ~~~~~~~^~~ main.cpp:36:22: note: within this loop for(int i = 1; i <= NMAX; i++) ~~^~~~~~~