Compilare: user.cpp: In function ‘int main()’: user.cpp:51:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<C.size();++i) { ^ user.cpp:54:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<C[i].size();++j) ^ user.cpp:37:21: warning: unused variable ‘a’ [-Wunused-variable] int n, i, x, y, a, b, sum=0,m,j; ^ user.cpp:37:24: warning: unused variable ‘b’ [-Wunused-variable] int n, i, x, y, a, b, sum=0,m,j; ^ user.cpp:37:27: warning: unused variable ‘sum’ [-Wunused-variable] int n, i, x, y, a, b, sum=0,m,j; ^ user.cpp: In function ‘void DFS(int, int, int)’: user.cpp:81:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[x].size();++i) { ^