Compilare: main.cpp: In function 'int main()': main.cpp:11:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int l = 1; 3 * l < s.size(); l ++) ~~~~~~^~~~~~~~~~ main.cpp:14:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i + 2 * l < s.size(); i ++) ~~~~~~~~~~^~~~~~~~~~ main.cpp:7:9: warning: unused variable 'n' [-Wunused-variable] int n; ^