Compilare: user.cpp: In function ‘bool f(int)’: user.cpp:16:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] int index = next[pos][w[i]] + k - 1; ^ user.cpp:18:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(index >= V[w[i]].size()) return 0; ^ user.cpp:18:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(index >= V[w[i]].size()) return 0; ~~~~~~^~~~~~~~~~~~~~~~~ user.cpp:19:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] pos = V[w[i]][index] + 1; ^ user.cpp: In function ‘int main()’: user.cpp:37:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] V[v[i]].push_back(i); ^ user.cpp:38:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] ind[i] = V[v[i]].size() - 1; ^ user.cpp:47:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] next[i][v[i]] = ind[i]; ^ user.cpp:31:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &q); ^