Compilare: main.cpp: In function 'int main()': main.cpp:228:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(r + pas < trees.size() && trees[r + pas]._Query(qleft[i], qright[i]) < kth[i]) ~~~~~~~~^~~~~~~~~~~~~~ main.cpp:195:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("engineer.in", "r", stdin); ^ main.cpp:196:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("engineer.out", "w", stdout); ^ main.cpp:197:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:202:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^ main.cpp:207:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &q); ^ main.cpp:211:53: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &qleft[i].first, &qleft[i].second); ^ main.cpp:212:55: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &qright[i].first, &qright[i].second); ^ main.cpp:213:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &kth[i]); ^