序列的美观度

思路

• 如果是连续相同的序列一定需要保留
  如果是不连续则记录下来，后面遇到有相同的就删掉其他那些

代码

// Problem: 序列的美观度
// Contest: NowCoder
// URL: https://ac.nowcoder.com/acm/contest/9983/I
// Memory Limit: 524288 MB
// Time Limit: 4000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp(aa,bb) make_pair(aa,bb)
#define _for(i,b) for(int i=(0);i<(b);i++)
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,b,a) for(int i=(b);i>=(a);i--)
#define mst(abc,bca) memset(abc,bca,sizeof abc)
#define X first
#define Y second
#define lowbit(a) (a&(-a))
#define debug(a) cout<<#a<<":"<<a<<"\n"
typedef long long ll;
typedef pair<int,int> pii;
typedef unsigned long long ull;
typedef long double ld;
const int N=1000010;
const int INF=0x3f3f3f3f;
const int mod=1e9+7;
const double eps=1e-6;
const double PI=acos(-1.0);

int a[N],ans;
set<int> s;

void solve(){
    int n;cin>>n;
    rep(i,1,n) cin>>a[i];
    rep(i,1,n){
        if(s.find(a[i])==s.end()) s.insert(a[i]);
        else {
            ans++;
            if(s.size()>1) {
                s.clear();
                s.insert(a[i]);
            }
        }
    }
    cout<<ans<<"\n";
}


int main(){
    ios::sync_with_stdio(0);cin.tie(0);
//    int t;cin>>t;while(t--)
    solve();
    return 0;
}