#ifdef DEBUG
#define _GLIBCXX_DEBUG
#endif
//#pragma GCC optimize("O3")
#include<bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include "lib/debug.h"
#else
#define debug(...) 228
#endif
typedef long long ll;
typedef long double ld;
#define pb push_back
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define F0R(i, a) FOR(i, 0, a)
vector<int> read_vec(int n) {
vector<int> v(n);
for (int& t : v) cin >> t;
return v;
}
template<typename T>
inline void upd_max(T& a, T b) {
if (a < b) {
a = b;
}
}
template<typename T>
inline void upd_min(T& a, T b) {
if (a > b) {
a = b;
}
}
int n;
const int maxN = 2e6 + 10;
int a[maxN];
int pref[maxN];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#ifdef DEBUG
freopen("input.txt", "r", stdin);
#endif
cin >> n;
FOR(i, 1, n + 1) {
cin >> a[i];
a[i + n] = a[i];
}
vector<pair<int,int>> st;
FOR(i, 1, 2 * n + 1) {
//a[j] >= a[i]
while (!st.empty() && st.back().first < a[i]) st.pop_back();
if (i > n) {
int z = st.back().second;
if (z <= i - n) {
pref[1]++;
}
else {
//[z +1;
int L = z % n + 1;
int R = i - n;
//[L .. R]
if (L <= R) {
pref[L]++;
pref[R + 1]--;
}
else {
pref[1]++;
pref[R + 1]--;
pref[L]++;
}
}
}
st.emplace_back(a[i], i);
}
int mx = 0;
FOR(i, 1, n + 1) {
pref[i] += pref[i - 1];
upd_max(mx, pref[i]);
}
cout << mx << '\n';
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 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 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | #ifdef DEBUG #define _GLIBCXX_DEBUG #endif //#pragma GCC optimize("O3") #include<bits/stdc++.h> using namespace std; #ifdef DEBUG #include "lib/debug.h" #else #define debug(...) 228 #endif typedef long long ll; typedef long double ld; #define pb push_back #define FOR(i, a, b) for (int i = (a); i < (b); ++i) #define F0R(i, a) FOR(i, 0, a) vector<int> read_vec(int n) { vector<int> v(n); for (int& t : v) cin >> t; return v; } template<typename T> inline void upd_max(T& a, T b) { if (a < b) { a = b; } } template<typename T> inline void upd_min(T& a, T b) { if (a > b) { a = b; } } int n; const int maxN = 2e6 + 10; int a[maxN]; int pref[maxN]; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); #ifdef DEBUG freopen("input.txt", "r", stdin); #endif cin >> n; FOR(i, 1, n + 1) { cin >> a[i]; a[i + n] = a[i]; } vector<pair<int,int>> st; FOR(i, 1, 2 * n + 1) { //a[j] >= a[i] while (!st.empty() && st.back().first < a[i]) st.pop_back(); if (i > n) { int z = st.back().second; if (z <= i - n) { pref[1]++; } else { //[z +1; int L = z % n + 1; int R = i - n; //[L .. R] if (L <= R) { pref[L]++; pref[R + 1]--; } else { pref[1]++; pref[R + 1]--; pref[L]++; } } } st.emplace_back(a[i], i); } int mx = 0; FOR(i, 1, n + 1) { pref[i] += pref[i - 1]; upd_max(mx, pref[i]); } cout << mx << '\n'; return 0; } |
English