#include <bits/stdc++.h>
// cut here
#ifdef _MSC_VER
#include <intrin.h>
#endif
namespace atcoder {
namespace internal {
int ceil_pow2(int n) {
int x = 0;
while ((1U << x) < (unsigned int)(n)) x++;
return x;
}
int bsf(unsigned int n) {
#ifdef _MSC_VER
unsigned long index;
_BitScanForward(&index, n);
return index;
#else
return __builtin_ctz(n);
#endif
}
} // namespace internal
} // namespace atcoder
namespace atcoder {
template <class S, S (*op)(S, S), S (*e)()> struct segtree {
public:
segtree() : segtree(0) {}
segtree(int n) : segtree(std::vector<S>(n, e())) {}
segtree(const std::vector<S>& v) : _n(int(v.size())) {
log = internal::ceil_pow2(_n);
size = 1 << log;
d = std::vector<S>(2 * size, e());
for (int i = 0; i < _n; i++) d[size + i] = v[i];
for (int i = size - 1; i >= 1; i--) {
update(i);
}
}
void set(int p, S x) {
assert(0 <= p && p < _n);
p += size;
d[p] = x;
for (int i = 1; i <= log; i++) update(p >> i);
}
S get(int p) {
assert(0 <= p && p < _n);
return d[p + size];
}
S prod(int l, int r) {
assert(0 <= l && l <= r && r <= _n);
S sml = e(), smr = e();
l += size;
r += size;
while (l < r) {
if (l & 1) sml = op(sml, d[l++]);
if (r & 1) smr = op(d[--r], smr);
l >>= 1;
r >>= 1;
}
return op(sml, smr);
}
S all_prod() { return d[1]; }
template <bool (*f)(S)> int max_right(int l) {
return max_right(l, [](S x) { return f(x); });
}
template <class F> int max_right(int l, F f) {
assert(0 <= l && l <= _n);
assert(f(e()));
if (l == _n) return _n;
l += size;
S sm = e();
do {
while (l % 2 == 0) l >>= 1;
if (!f(op(sm, d[l]))) {
while (l < size) {
l = (2 * l);
if (f(op(sm, d[l]))) {
sm = op(sm, d[l]);
l++;
}
}
return l - size;
}
sm = op(sm, d[l]);
l++;
} while ((l & -l) != l);
return _n;
}
template <bool (*f)(S)> int min_left(int r) {
return min_left(r, [](S x) { return f(x); });
}
template <class F> int min_left(int r, F f) {
assert(0 <= r && r <= _n);
assert(f(e()));
if (r == 0) return 0;
r += size;
S sm = e();
do {
r--;
while (r > 1 && (r % 2)) r >>= 1;
if (!f(op(d[r], sm))) {
while (r < size) {
r = (2 * r + 1);
if (f(op(d[r], sm))) {
sm = op(d[r], sm);
r--;
}
}
return r + 1 - size;
}
sm = op(d[r], sm);
} while ((r & -r) != r);
return 0;
}
private:
int _n, size, log;
std::vector<S> d;
void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
};
} // namespace atcoder
// cut here
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define rng(i,c,n) for(int i=c;i<n;i++)
#define fi first
#define se second
#define vec vector
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(),a.end()
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
void print(){cout<<'\n';}
template<class h,class...t>
void print(const h&v,const t&...u){cout<<v<<' ',print(u...);}
int op(int l,int r){
return l+r;
}
int e(){
return 0;
}
void slv(){
int n;
cin>>n;
const int n2=n*2;
vi a(n2);
rep(i,n){
cin>>a[i];
}
rep(i,n2){
a[i]=a[i%n];
}
int ans=0;
atcoder::segtree<int,op,e> seg(n2);
vi stk;
per(i,n2){
while(sz(stk) and a[i]>=a[stk.back()]){
// if(stk.back()==4) print(i,a[i]);
seg.set(stk.back(),0);
stk.pop_back();
}
stk.pb(i);
seg.set(stk.back(),1);
ans=max(ans,seg.prod(i,min(i+n,n2)));
// if(i==2){
// rep(j,n) cout<<seg.get(i+j)<<" ";
// print();
// }
}
cout<<ans<<"\n";
}
signed main(){
ios::sync_with_stdio(0),cin.tie(0);
int t;
t=1;
// cin>>t;
rep(cs,t){
slv();
}
}
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 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 | #include <bits/stdc++.h> // cut here #ifdef _MSC_VER #include <intrin.h> #endif namespace atcoder { namespace internal { int ceil_pow2(int n) { int x = 0; while ((1U << x) < (unsigned int)(n)) x++; return x; } int bsf(unsigned int n) { #ifdef _MSC_VER unsigned long index; _BitScanForward(&index, n); return index; #else return __builtin_ctz(n); #endif } } // namespace internal } // namespace atcoder namespace atcoder { template <class S, S (*op)(S, S), S (*e)()> struct segtree { public: segtree() : segtree(0) {} segtree(int n) : segtree(std::vector<S>(n, e())) {} segtree(const std::vector<S>& v) : _n(int(v.size())) { log = internal::ceil_pow2(_n); size = 1 << log; d = std::vector<S>(2 * size, e()); for (int i = 0; i < _n; i++) d[size + i] = v[i]; for (int i = size - 1; i >= 1; i--) { update(i); } } void set(int p, S x) { assert(0 <= p && p < _n); p += size; d[p] = x; for (int i = 1; i <= log; i++) update(p >> i); } S get(int p) { assert(0 <= p && p < _n); return d[p + size]; } S prod(int l, int r) { assert(0 <= l && l <= r && r <= _n); S sml = e(), smr = e(); l += size; r += size; while (l < r) { if (l & 1) sml = op(sml, d[l++]); if (r & 1) smr = op(d[--r], smr); l >>= 1; r >>= 1; } return op(sml, smr); } S all_prod() { return d[1]; } template <bool (*f)(S)> int max_right(int l) { return max_right(l, [](S x) { return f(x); }); } template <class F> int max_right(int l, F f) { assert(0 <= l && l <= _n); assert(f(e())); if (l == _n) return _n; l += size; S sm = e(); do { while (l % 2 == 0) l >>= 1; if (!f(op(sm, d[l]))) { while (l < size) { l = (2 * l); if (f(op(sm, d[l]))) { sm = op(sm, d[l]); l++; } } return l - size; } sm = op(sm, d[l]); l++; } while ((l & -l) != l); return _n; } template <bool (*f)(S)> int min_left(int r) { return min_left(r, [](S x) { return f(x); }); } template <class F> int min_left(int r, F f) { assert(0 <= r && r <= _n); assert(f(e())); if (r == 0) return 0; r += size; S sm = e(); do { r--; while (r > 1 && (r % 2)) r >>= 1; if (!f(op(d[r], sm))) { while (r < size) { r = (2 * r + 1); if (f(op(d[r], sm))) { sm = op(d[r], sm); r--; } } return r + 1 - size; } sm = op(d[r], sm); } while ((r & -r) != r); return 0; } private: int _n, size, log; std::vector<S> d; void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); } }; } // namespace atcoder // cut here using namespace std; #define rep(i,n) for(int i=0;i<n;i++) #define per(i,n) for(int i=n-1;i>=0;i--) #define rng(i,c,n) for(int i=c;i<n;i++) #define fi first #define se second #define vec vector #define pb push_back #define sz(a) (int)a.size() #define all(a) a.begin(),a.end() typedef long long ll; typedef vector<int> vi; typedef pair<int,int> pii; void print(){cout<<'\n';} template<class h,class...t> void print(const h&v,const t&...u){cout<<v<<' ',print(u...);} int op(int l,int r){ return l+r; } int e(){ return 0; } void slv(){ int n; cin>>n; const int n2=n*2; vi a(n2); rep(i,n){ cin>>a[i]; } rep(i,n2){ a[i]=a[i%n]; } int ans=0; atcoder::segtree<int,op,e> seg(n2); vi stk; per(i,n2){ while(sz(stk) and a[i]>=a[stk.back()]){ // if(stk.back()==4) print(i,a[i]); seg.set(stk.back(),0); stk.pop_back(); } stk.pb(i); seg.set(stk.back(),1); ans=max(ans,seg.prod(i,min(i+n,n2))); // if(i==2){ // rep(j,n) cout<<seg.get(i+j)<<" "; // print(); // } } cout<<ans<<"\n"; } signed main(){ ios::sync_with_stdio(0),cin.tie(0); int t; t=1; // cin>>t; rep(cs,t){ slv(); } } |
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