Compilare: main.cpp: In function 'int main()': main.cpp:181:15: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses] if(v[i].first==v[j].first) ^ main.cpp:121:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("popandai.in","r",stdin); ^ main.cpp:123:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("popandai.out","w",stdout); ^ main.cpp:129:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ main.cpp:135:47: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&v[i].first,&v[i].second); ^