#include <bits/stdc++.h>
using namespace std;
#define fwd(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n) fwd(i, 0, n)
#define all(X) X.begin(), X.end()
#define sz(X) int(size(X))
#define pb push_back
#define eb emplace_back
#define st first
#define nd second
using pii = pair<int, int>; using vi = vector<int>;
using ll = long long; using ld = long double;
#ifdef LOC
auto SS = signal(6, [](int) { *(int *)0 = 0; });
#define DTP(x, y) auto operator << (auto &o, auto a) -> decltype(y, o) { o << "("; x; return o << ")"; }
DTP(o << a.st << ", " << a.nd, a.nd);
DTP(for (auto i : a) o << i << ", ", all(a));
void dump(auto... x) { (( cerr << x << ", " ), ...) << '\n'; }
#define deb(x...) cerr << setw(4) << __LINE__ << ":[" #x "]: ", dump(x)
#else
#define deb(...) 0
#endif
void solve() {
int n;
cin >> n;
vi A(n+1);
for(int i = 1; i <= n; i++) {
cin >> A[i];
}
for(int i = 1; i <= n; i++) {
A.pb(A[i]);
}
n *= 2;
// when I am max on prefix, so first to the left >= me
vi leftt(n+1);
A[0] = 1e9;
for(int i = 1; i <= n; i++) {
int b = i-1;
while(A[b] < A[i])
b = leftt[b];
leftt[i] = b;
}
vi pref(n+2);
for(int i = 1; i <= n; i++) {
int x = max(leftt[i]+1, i - n/2 + 1);
pref[x]++;
pref[i+1]--;
}
int res = 1;
for(int i = 2; i <= n; i++) {
pref[i] += pref[i-1];
res = max(res, pref[i]);
}
cout << res << "\n";
}
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cout << fixed << setprecision(10);
solve();
}
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 | #include <bits/stdc++.h> using namespace std; #define fwd(i, a, n) for (int i = (a); i < (n); i++) #define rep(i, n) fwd(i, 0, n) #define all(X) X.begin(), X.end() #define sz(X) int(size(X)) #define pb push_back #define eb emplace_back #define st first #define nd second using pii = pair<int, int>; using vi = vector<int>; using ll = long long; using ld = long double; #ifdef LOC auto SS = signal(6, [](int) { *(int *)0 = 0; }); #define DTP(x, y) auto operator << (auto &o, auto a) -> decltype(y, o) { o << "("; x; return o << ")"; } DTP(o << a.st << ", " << a.nd, a.nd); DTP(for (auto i : a) o << i << ", ", all(a)); void dump(auto... x) { (( cerr << x << ", " ), ...) << '\n'; } #define deb(x...) cerr << setw(4) << __LINE__ << ":[" #x "]: ", dump(x) #else #define deb(...) 0 #endif void solve() { int n; cin >> n; vi A(n+1); for(int i = 1; i <= n; i++) { cin >> A[i]; } for(int i = 1; i <= n; i++) { A.pb(A[i]); } n *= 2; // when I am max on prefix, so first to the left >= me vi leftt(n+1); A[0] = 1e9; for(int i = 1; i <= n; i++) { int b = i-1; while(A[b] < A[i]) b = leftt[b]; leftt[i] = b; } vi pref(n+2); for(int i = 1; i <= n; i++) { int x = max(leftt[i]+1, i - n/2 + 1); pref[x]++; pref[i+1]--; } int res = 1; for(int i = 2; i <= n; i++) { pref[i] += pref[i-1]; res = max(res, pref[i]); } cout << res << "\n"; } int32_t main() { cin.tie(0)->sync_with_stdio(0); cout << fixed << setprecision(10); solve(); } |
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