Compilare: main.cpp: In function 'int main()': main.cpp:64:55: warning: format '%d' expects argument of type 'int', but argument 3 has type 'std::vector<std::pair<char, int> >::size_type {aka long unsigned int}' [-Wformat=] fprintf(fout,"%d\n" ,sol[0].size() + sol[1].size()); ^ main.cpp:40:25: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&n); ^ main.cpp:42:64: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&son[0][i].first,&son[0][i].second); ^ main.cpp:53:64: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&son[1][i].first,&son[1][i].second); ^ main.cpp:57:9: warning: 'root1' may be used uninitialized in this function [-Wmaybe-uninitialized] int root1; ^~~~~ main.cpp:46:9: warning: 'root0' may be used uninitialized in this function [-Wmaybe-uninitialized] int root0; ^~~~~