import sys,io,os
try:Z=io.BytesIO(os.read(0,os.fstat(0).st_size)).readline
except:Z=lambda:sys.stdin.readline().encode()
Y=lambda:map(sub,Z().split())
sub=lambda x:int(x)-1
n=int(Z());a=[*Y()];L=[-1]*n
for i in range(n):L[a[i]]=i
for x in range(n):
if x!=L[a[x]]:break
s={a[x]};ns=set();r=0
for i in range(x+1,n):
if s:
if i==L[a[i]]:
if a[i]in ns:ns.remove(a[i])
elif a[i]in s:
s.remove(a[i])
if not s:s,ns=ns,set();r-=1
elif a[i]not in s:ns.add(a[i])
r+=1
elif i!=L[a[i]]:s.add(a[i])
print(r)#include <algorithm>
#include <deque>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>
using namespace std;
typedef long long ll;
typedef vector<int> veci;
typedef vector<ll> vecll;
long long mod = 998244353;
int main(){
int n;
cin >> n;
vector<int> a(n, 0);
for(auto& x : a) cin >> x;
map<int, int> l, r;
for(int i = n - 1; i >= 0; --i){
if(r.find(a[i]) == r.end()) r[a[i]] = i;
}
int m = 0, begin = 0, end, pivot = 1;
while(begin < n){
//cerr << "begin : " << begin <<endl;
end = r[a[begin]];
++m;
//cerr << "increment " << m << endl;
pivot = max(pivot, begin + 1);
int new_begin = -1, new_end = -1;
while(pivot < end){
if(r[a[pivot]] > end){
if(r[a[pivot]] > new_end){
new_end = r[a[pivot]];
new_begin = pivot;
}
}
++pivot;
}
if(new_begin == -1){
//cerr << "next chunk" << endl;
if(end > begin) ++m;
//cerr << "increment " << m << endl;
begin = end + 1;
}
else{
begin = new_begin;
}
}
cout << n - m << endl;
}383. Ransom Note | 242. Valid Anagram |
141. Linked List Cycle | 21. Merge Two Sorted Lists |
203. Remove Linked List Elements | 733. Flood Fill |
206. Reverse Linked List | 83. Remove Duplicates from Sorted List |
116. Populating Next Right Pointers in Each Node | 145. Binary Tree Postorder Traversal |
94. Binary Tree Inorder Traversal | 101. Symmetric Tree |
77. Combinations | 46. Permutations |
226. Invert Binary Tree | 112. Path Sum |
1556A - A Variety of Operations | 136. Single Number |
169. Majority Element | 119. Pascal's Triangle II |
409. Longest Palindrome | 1574A - Regular Bracket Sequences |
1574B - Combinatorics Homework | 1567A - Domino Disaster |
1593A - Elections | 1607A - Linear Keyboard |
EQUALCOIN Equal Coins | XOREQN Xor Equation |
MAKEPAL Weird Palindrome Making | HILLSEQ Hill Sequence |