Compilare: user.cpp: In function ‘void refresh(int)’: user.cpp:38:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < aint[2 * nod].size() && j < aint[2 * nod + 1].size()) { ^ user.cpp:38:66: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < aint[2 * nod].size() && j < aint[2 * nod + 1].size()) { ^ user.cpp:48:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < aint[2 * nod].size()) { ^ user.cpp:52:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < aint[2 * nod + 1].size()) { ^ user.cpp: In function ‘void query(int, int, int, int, int)’: user.cpp:96:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < ans && j < aint[nod].size()) { ^ user.cpp:110:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < aint[nod].size()) { ^ user.cpp: In function ‘char nextch()’: user.cpp:13:34: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, 1, MAXBUF, fi); ^