ARC 103 /\/\/\/ 题解

前缀和一下，就好了

#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
const int N=1e5+99;
int a[N],odd[N],even[N];
struct cmp
{
	bool operator () (int A,int B)
	{
		return odd[A]<odd[B];
	}
};
struct cmp1
{
	bool operator () (int A,int B) 
	{
		return even[A]<even[B];
	}
};
priority_queue<int,vector<int> ,cmp>qo;
priority_queue<int,vector<int> ,cmp1>qe;

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin>>n;
	for(int i=1;i<=n;++i)
	{
		cin>>a[i];
		if(i&1)
		{
			odd[a[i]]++;
		}
		else
		{
			even[a[i]]++;
		}
	}
	for(int i=1;i<=N;++i)
	{
		qo.push(i);
		qe.push(i);
	}
	if(qo.top()!=qe.top())
	{
		cout<<n-odd[qo.top()]-even[qe.top()];
	}
	else
	{
		int t1=odd[qo.top()];qo.pop();
		int t2=even[qe.top()];
		qe.pop();
		cout<<n-max(t2+odd[qo.top()],t1+even[qe.top()]);
	}
}