Compilare: main.cpp: In function 'int main()': main.cpp:16:4: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for( j = 1 ; j <= m ; st.push_back({s,j}), ++ j , s.clear() ) ^~~ main.cpp:19:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' sort( st.begin() , st.end() ) ; ^~~~ main.cpp:20:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < st.size() ; ++ i ) out << st [ i ].second << ' ' ; ~~^~~~~~~~~~~