// #include <bits/stdc++.h> #include <iostream> #include <cmath> #include <algorithm> #include <map> #include <unordered_map> #include <vector> #include <iomanip> #include <string> #include <queue> #include <set> #include <deque> using namespace std; #define int long long #define endl "\n" #define fi first #define se second const int M=1e9+7; const int inf = 1e14; const int LOG=18; const int N=7e1+5; int n , m , c , w , k , t=1 , q=1 , x , y , z , l , r; void solve(){ cin >> n; vector<int>a(n); for (int i=0;i<n;i++){ cin >> a[i]; } if (n<=2000){ c=0; for (int i=0;i<n;i++){ map<int,int>d; int cn=0; for (int j=i;j<n;j++){ d[a[j]]++; cn=max(cn,d[a[j]]); if (cn>(j-i+1)/2)c++; } } cout << c << endl; return; } c=n*(n+1)/2; map<int,int>d; d[0]=1; int c1=0,c2=0; for (int i=0;i<n;i++){ c1+=a[i]==1; c2+=a[i]==2; c-=d[c1-c2]; d[c1-c2]++; } cout << c << endl; } signed main() { // ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE // cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE cout << fixed << setprecision(9); srand(time(0)); // int t=1; // cin >> t; for (int _=1;_<=t;_++){ solve(); q++; } }