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| #include <bits/stdc++.h>
#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
struct PairHash {inline std::size_t operator()(const std::pair<int,int> & v) const {return v.first*31+v.second;}};
#define MAX_N 252525
#define INF 987654321
#define EPS 1e-9
#define ll long long
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vall3 vector<array<ll,3>>
#define all3 array<ll,3>
#define all5 array<ll,5>
#define vall5 vector<all5>
#define vll vector<ll>
#define vi vector<int>
#define vs vector<string>
#define usll unordered_set<ll>
#define uspll unordered_set<pll, PairHash>
#define umll unordered_map<ll,ll>
#define vvs vector<vs>
#define vvll vector<vll>
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
ll __gcd(ll x, ll y) { return !y ? x : __gcd(y, x % y); }
using namespace std;
ll helper(vll& A, ll k) {
ll n = A.size(), res = 0, l = 0, r = 0;
while(r < n and l < n) {
if(A[r] != k) r++;
else {
l = r;
while(r < n and A[r] == k) r++;
res += (r - l) * (r - l + 1) / 2;
l = r;
}
}
return res;
}
ll solve(vll& A, ll x, ll y) {
if(x == y) return helper(A, x);
ll n = A.size();
vll mist, mast, xvll, yvll;
vpll mir(n), mar(n);
for(ll i = 0; i <= n; i++) {
while(!mist.empty() and (i == n or A[mist.back()] > A[i])) {
auto j = mist.back(); mist.pop_back();
auto l = mist.empty() ? 0 : mist.back() + 1;
mir[j] = {l, i - 1};
}
mist.push_back(i);
while(!mast.empty() and (i == n or A[mast.back()] < A[i])) {
auto j = mast.back(); mast.pop_back();
auto l = mast.empty() ? 0 : mast.back() + 1;
mar[j] = {l, i - 1};
}
mast.push_back(i);
if(i != n and A[i] == x) xvll.push_back(i);
if(i != n and A[i] == y) yvll.push_back(i);
}
ll i = 0, j = 0, res = 0;
ll N = xvll.size(), M = yvll.size();
while(i < N and j < M) {
ll a = xvll[i], b = yvll[j];
auto [mile, miri] = mir[a];
auto [male, mari] = mar[b];
if(mile <= b and b <= miri and male <= a and a <= mari) {
auto l = max(mile, male), r = min(miri, mari);
auto lb = min(a, b) - l + 1, rb = r - max(a,b) + 1;
res += lb * rb;
}
if(a < b) i++;
else j++;
}
return res;
}
int main() {
ios_base::sync_with_stdio(0);
ios::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
for(ll i = 1; i <= tc; i++) {
ll n, ma, mi;
cin>>n>>ma>>mi;
vll A(n);
for(ll j = 0; j < n; j++) cin>>A[j];
cout<<solve(A, mi, ma)<<endl;
}
return 0;
}
|
