Compilare: main.cpp: In function 'int main()': main.cpp:50:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(h.size()<k) ~~~~~~~~^~ main.cpp:30:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("banana.in", "r", stdin); ^ main.cpp:31:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("banana.out", "w", stdout); ^ main.cpp:34:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ main.cpp:38:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^