Compilare: main.cpp: In function 'void bell(int)': main.cpp:40:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(p = 0; p < nd[x].size(); p++){ ~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:80:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bal2.in", "r", stdin); ^ main.cpp:81:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bal2.out", "w", stdout); ^ main.cpp:84:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ main.cpp:88:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &p); ^