#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;
int arr[2000001];
int jump[2000001][21];
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//random_start();
int n;
cin >> n;
rep(i,n)
{
cin >> arr[i];
arr[i+n] = arr[i];
}
stack<int> st;
st.push(n*2);
arr[n*2] = 1e9+1;
jump[n*2][0] = n*2;
for(int i = n*2-1; i >= 0; i--)
{
while(arr[st.top()] <= arr[i]) st.pop();
jump[i][0] = st.top();
st.push(i);
}
rep2(bit,1,20) rep(i,n*2+1) jump[i][bit] = jump[jump[i][bit-1]][bit-1];
int ans = 0;
rep(i,n)
{
int cur = i;
int ans2 = 1;
for(int bit = 20; bit >= 0; bit--)
{
int cur2 = jump[cur][bit];
if(cur2 < i+n)
{
ans2 += (1<<bit);
cur = cur2;
}
}
ans = max(ans,ans2);
}
cout << ans << "\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 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 | #include <bits/stdc++.h> #pragma GCC optimize("O3,unroll-loops") #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt") #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> #define ll long long #define ld long double #define ull unsigned long long #define ff first #define ss second #define pii pair<int,int> #define pll pair<long long, long long> #define vi vector<int> #define vl vector<long long> #define pb push_back #define rep(i, b) for(int i = 0; i < (b); ++i) #define rep2(i,a,b) for(int i = a; i <= (b); ++i) #define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c) #define count_bits(x) __builtin_popcountll((x)) #define all(x) (x).begin(),(x).end() #define siz(x) (int)(x).size() #define forall(it,x) for(auto& it:(x)) using namespace __gnu_pbds; using namespace std; typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set; //mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());} //ll los(ll a, ll b) {return a + (mt() % (b-a+1));} const int INF = 1e9+50; const ll INF_L = 1e18+40; const ll MOD = 1e9+7; int arr[2000001]; int jump[2000001][21]; int main() { ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0); //random_start(); int n; cin >> n; rep(i,n) { cin >> arr[i]; arr[i+n] = arr[i]; } stack<int> st; st.push(n*2); arr[n*2] = 1e9+1; jump[n*2][0] = n*2; for(int i = n*2-1; i >= 0; i--) { while(arr[st.top()] <= arr[i]) st.pop(); jump[i][0] = st.top(); st.push(i); } rep2(bit,1,20) rep(i,n*2+1) jump[i][bit] = jump[jump[i][bit-1]][bit-1]; int ans = 0; rep(i,n) { int cur = i; int ans2 = 1; for(int bit = 20; bit >= 0; bit--) { int cur2 = jump[cur][bit]; if(cur2 < i+n) { ans2 += (1<<bit); cur = cur2; } } ans = max(ans,ans2); } cout << ans << "\n"; } |
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