题解

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>  
using namespace __gnu_pbds;              
using namespace std;

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_set;  
int N, h, ans;
vector<int> height;
indexed_set cow; 
indexed_set woc;  
int main() {
	cin>>N;
	for (int i = 0; i < N; i++) {
		cin>>h;
		cow.insert(h);
		height.push_back(h);
	}
	for (int i : height) {
		cow.erase(i);  
		int le =
		    woc.size() -
		    woc.order_of_key(i);  
		                        
		int ri =cow.size() - cow.order_of_key(i);  
		woc.insert(i);                       
		if (max(le, ri) > 2 * min(le, ri)) ans++;
	}
	cout<<ans;
}