Compilare: main.cpp: In function 'int main()': main.cpp:20:63: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!st.empty() and st.back()<s[i] and st.size()+n-i>m) ~~~~~~~~~~~~~^~ main.cpp:22:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st.size()<m) ~~~~~~~~~^~