Compilare: user.cpp: In function ‘void update(int, int)’: user.cpp:17:41: warning: suggest parentheses around arithmetic in operand of ‘^’ [-Wparentheses] for (; idx <= n; idx += idx^(idx-1) & idx) ^ user.cpp: In function ‘int query(int)’: user.cpp:24:36: warning: suggest parentheses around arithmetic in operand of ‘^’ [-Wparentheses] for (; idx; idx -= idx^(idx-1) & idx) ^ user.cpp: In function ‘int main()’: user.cpp:40:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("scmax.in", "r", stdin); ^ user.cpp:41:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("scmax.out", "w", stdout); ^ user.cpp:44:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:46:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^