#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define st first
#define nd second
#define pii pair<int,int>
#define pb push_back
#define pp pop_back
#define si size
#define int ll
#define V vector
#define pf push_front
#define ppf pop_front
#define fr front
#define ba back
;
#define cerr if(0) cerr
int dp[2];
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n,ma=0;
cin>>n;
vector<int> v(n);
deque<pii> d;
for(int i=0;i<n;i++){
cin>>v[i];
if(v[i]>ma)d.pb({v[i],i}),ma=v[i];
}
ma=d.si();
// cout<<ma<<'\n';
for(int i=n-1;i>=0;i--){
int a=v[i];
if(d.ba()==make_pair(v[i],i))d.pp();
while(d.si()&&d.fr().st<=v[i])d.ppf();
d.pf({v[i],i});
ma=max(ma,(int)d.si());
// cout<<i<<' '<<ma<<'\n';
// for(pii j : d)cout<<"("<<j.st<<' '<<j.nd<<") ";
// cout<<'\n';
}
cout<<ma<<'\n';
}
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 44 | #include <bits/stdc++.h> using namespace std; #define ll long long #define st first #define nd second #define pii pair<int,int> #define pb push_back #define pp pop_back #define si size #define int ll #define V vector #define pf push_front #define ppf pop_front #define fr front #define ba back ; #define cerr if(0) cerr int dp[2]; signed main(){ ios_base::sync_with_stdio(0); cin.tie(0); int n,ma=0; cin>>n; vector<int> v(n); deque<pii> d; for(int i=0;i<n;i++){ cin>>v[i]; if(v[i]>ma)d.pb({v[i],i}),ma=v[i]; } ma=d.si(); // cout<<ma<<'\n'; for(int i=n-1;i>=0;i--){ int a=v[i]; if(d.ba()==make_pair(v[i],i))d.pp(); while(d.si()&&d.fr().st<=v[i])d.ppf(); d.pf({v[i],i}); ma=max(ma,(int)d.si()); // cout<<i<<' '<<ma<<'\n'; // for(pii j : d)cout<<"("<<j.st<<' '<<j.nd<<") "; // cout<<'\n'; } cout<<ma<<'\n'; } |
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