Compilare: main.cpp: In function 'int main()': main.cpp:55:33: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<std::pair<char, char> >::size_type {aka long unsigned int}' [-Wformat=] printf("2 %d\n" , sol.size()); ^ main.cpp:56:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < sol.size() ; i ++) ~~^~~~~~~~~~~~ main.cpp:43:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("aranjare3.in" , "r" , stdin); ^ main.cpp:44:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("aranjare3.out" , "w" , stdout); ^ main.cpp:46:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^ main.cpp:49:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &x); ^