Compilare: main.cpp: In function 'void upd(int, int)': main.cpp:44:27: warning: unused variable 'w' [-Wunused-variable] int b = first[id[a]], w = id[a]; ^ main.cpp: In function 'int main()': main.cpp:50:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pensula.in", "r", stdin); ^ main.cpp:51:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pensula.out", "w", stdout); ^ main.cpp:52:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &n, &M, &Q, &C); ^ main.cpp:54:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t[i]); ^