Compilare: user.cpp: In function ‘int query(int)’: user.cpp:118:9: warning: unused variable ‘i’ [-Wunused-variable] int i, res = 0; ^ user.cpp: In function ‘void DFS(int, int)’: user.cpp:130:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < knode[x].size(); ++ i) ^ user.cpp:140:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < G[x].size(); ++ i) ^ user.cpp:127:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp: In function ‘void solve()’: user.cpp:189:12: warning: unused variable ‘x’ [-Wunused-variable] int i, x, y, k; ^ user.cpp:189:15: warning: unused variable ‘y’ [-Wunused-variable] int i, x, y, k; ^ user.cpp:189:18: warning: unused variable ‘k’ [-Wunused-variable] int i, x, y, k; ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:22:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^