Compilare: main.cpp: In function 'int main()': main.cpp:49:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= xlist.size() + 1; ++i) ~~^~~~~~~~~~~~~~~~~~~ main.cpp:50:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 1; j <= ylist.size() + 1; ++j) ~~^~~~~~~~~~~~~~~~~~~ main.cpp:40:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("agora.in", "r", stdin); ^ main.cpp:41:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("agora.out", "w", stdout); ^ main.cpp:42:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &q); ^ main.cpp:58:82: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] y2 = distance(ylist.begin(), upper_bound(ylist.begin(), ylist.end(), y2)); ^