Compilare: user.cpp: In function ‘int solve(int, int)’: user.cpp:11:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < min(s[a].length(),s[b].length()); i ++) if (s[a][i] != s[b][i]) break; ^ user.cpp:10:11: warning: unused variable ‘x’ [-Wunused-variable] int i,x,y; ^ user.cpp:10:13: warning: unused variable ‘y’ [-Wunused-variable] int i,x,y; ^