Compilare: main.cpp: In function 'bool is(int)': main.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j < v[i].size() ; j++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:31:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < st.size() ; i++){ ~~^~~~~~~~~~~ main.cpp:52:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < st.size() ; i++){ ~~^~~~~~~~~~~ main.cpp:61:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = st.size() ; i < s.size() ; i++){ ~~^~~~~~~~~~ main.cpp:26:23: warning: unused variable 'j' [-Wunused-variable] int i,x,y,ans = 0,j; ^