Compilare: main.cpp: In member function 'void QuadTree::init(int, int, int, int, int)': main.cpp:24:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] int midx = x + x2 >> 1; ~~^~~~ main.cpp:25:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] int midy = y + y2 >> 1; ~~^~~~ main.cpp: In member function 'int QuadTree::query(int, int, int, int, int, int, int, int, int)': main.cpp:39:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] int midx = x + x2 >> 1; ~~^~~~ main.cpp:40:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] int midy = y + y2 >> 1; ~~^~~~ main.cpp: In function 'int main()': main.cpp:68:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("BEMO.in", "r", stdin); ^ main.cpp:69:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("BEMO.out", "w", stdout); ^ main.cpp:71:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:73:109: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (int i = 1; i <= n; i++) for (int j = 1; j <= m; j++) scanf("%d", &a[i][j]), where[a[i][j]] = {i, j}; ^