Compilare: main.cpp: In function 'int find(int)': main.cpp:14:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < map[hash].size(); i++) ~~^~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:36:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("proc2.in", "r", stdin); ^ main.cpp:37:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("proc2.out", "w", stdout); ^ main.cpp:40:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:43:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &op, &x); ^