Compilare: main.cpp: In function 'void solve()': main.cpp:119:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int it = 0; it < query_ind.size(); it++) ~~~^~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:146:36: 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); freopen("engineer.out", "w", stdout); ^ main.cpp:146:74: 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); freopen("engineer.out", "w", stdout); ^ main.cpp:148:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:152:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^ main.cpp:163:95: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &query[i].x1, &query[i].y1, &query[i].x2, &query[i].y2, &query[i].k); ^