alternating.cpp: In constructor 'Seg::Seg(int, int)':
alternating.cpp:25:46: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |     Seg (int _l, int _r) : l(_l), r(_r), m(l + r >> 1), mn(0), lz(0) {
      |                                            ~~^~~
alternating.cpp: In function 'int main()':
alternating.cpp:83:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |         for (; j < event.size() && event[j].X == i; ++j) {
      |                ~~^~~~~~~~~~~~~~