Compilare: main.cpp: In function 'int main()': main.cpp:49:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (last[j] < v[j].size() and v[j][last[j]] <= i){ ~~~~~~~~^~~~~~~~~~~~~ main.cpp:24:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("infinitywar.in", "r", stdin); ^ main.cpp:25:45: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("infinitywar.out", "w", stdout); ^ main.cpp:28:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &n, &Q); ^ main.cpp:32:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &k); ^ main.cpp:35:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &v[i][j]); ^ main.cpp:40:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &left[i]); ^ main.cpp:42:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &right[i]); ^