Compilare: user.cpp: In function ‘int main()’: user.cpp:55:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < ACM.size(); i++) ^ user.cpp:36:18: warning: unused variable ‘x’ [-Wunused-variable] int N, M, i, x, y, c; ^ user.cpp:36:21: warning: unused variable ‘y’ [-Wunused-variable] int N, M, i, x, y, c; ^ user.cpp:36:24: warning: unused variable ‘c’ [-Wunused-variable] int N, M, i, x, y, c; ^