#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define vc vector
#define st first
#define nd second
#define all(a) a.begin(), a.end()
#define sz(a) (ll)a.size()
#define pub push_back
#define pob pop_back
void program() {
ll n;
cin >> n;
vc<ll> a(n);
for (ll &ai : a)
cin >> ai;
deque<pll> dq;
for (ll i = 0; i < n; i++)
if (dq.empty() or a[i] > dq.back().nd)
dq.pub({i, a[i]});
ll ans = sz(dq);
for (ll i = n - 1; i >= 0; i--) {
if (dq.back().st == i)
dq.pob();
while (not dq.empty() and dq.front().nd <= a[i])
dq.pop_front();
dq.push_front({i, a[i]});
ans = max(ans, sz(dq));
}
cout << ans << "\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
program();
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | #include <bits/stdc++.h> using namespace std; typedef long long ll; typedef pair<ll, ll> pll; #define vc vector #define st first #define nd second #define all(a) a.begin(), a.end() #define sz(a) (ll)a.size() #define pub push_back #define pob pop_back void program() { ll n; cin >> n; vc<ll> a(n); for (ll &ai : a) cin >> ai; deque<pll> dq; for (ll i = 0; i < n; i++) if (dq.empty() or a[i] > dq.back().nd) dq.pub({i, a[i]}); ll ans = sz(dq); for (ll i = n - 1; i >= 0; i--) { if (dq.back().st == i) dq.pob(); while (not dq.empty() and dq.front().nd <= a[i]) dq.pop_front(); dq.push_front({i, a[i]}); ans = max(ans, sz(dq)); } cout << ans << "\n"; } int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); program(); return 0; } |
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