#include #define rep(i,n) for(int i=0;i<(int)(n);i++) #define rep1(i,n) for(int i=1;i<=(int)(n);i++) #define all(c) c.begin(),c.end() #define pb push_back #define fs first #define sc second #define show(x) cout << #x << " = " << x << endl #define chmin(x,y) x=min(x,y) #define chmax(x,y) x=max(x,y) using namespace std; template ostream& operator<<(ostream& o,const pair &p){return o<<"("< ostream& operator<<(ostream& o,const vector &vc){o<<"sz = "< segid[i] -> nxt D(){ segid[0]=segid[1]=-1; id[0]=id[1]=-1; mx[0]=mx[1]=-1; } D(int x){ segid[0]=x; segid[1]=-1; id[0]=-1; id[1]=-1; mx[0]=1; mx[1]=-1; } D(int a,int b,int c,int d,int e,int f){ id[0]=a,segid[0]=b,mx[0]=c,id[1]=d,segid[1]=e,mx[1]=f; } const static D e; D operator+(const D& r) const { typedef pair P; typedef pair PP; map mp; rep(i,2) if(mx[i]>=0) chmax(mp[id[i]],P(mx[i],segid[i])); rep(i,2) if(r.mx[i]>=0) chmax(mp[r.id[i]],P(r.mx[i],r.segid[i])); vector vp; for(auto it:mp) vp.pb(PP(it.sc,it.fs)); sort(all(vp),greater()); int K=vp.size(); D ret; rep(i,min(2,K)) ret.id[i]=vp[i].sc,ret.mx[i]=vp[i].fs.fs,ret.segid[i]=vp[i].fs.sc; return ret; } void inc(){ rep(i,2) if(mx[i]>=0) mx[i]++; } friend ostream& operator<<(ostream& o,const D& d){ o<<"d= mx="< struct segtree{ static const int N=1<<17; D e=D::e; vector seg; segtree():seg(N*2,e){} void update(int k,D val){ k+=N; seg[k]=val; k/=2; while(k){ seg[k]=seg[k*2]+seg[k*2+1]; k/=2; } } D calc(int a,int b,int l=0,int r=N,int k=1){ if(b<=a||b<=l||r<=a) return e; if(a<=l&&r<=b) return seg[k]; return calc(a,b,l,(l+r)/2,k*2)+calc(a,b,(l+r)/2,r,k*2+1); } }; segtree up,down; int N; int x[100000]; vector xs; int main(){ cin>>N; rep(i,N){ scanf("%d",x+i); xs.pb(x[i]); } sort(all(xs)); xs.erase(unique(xs.begin(),xs.end()),xs.end()); int K=xs.size(); rep(i,N) x[i]=lower_bound(all(xs),x[i])-xs.begin(); rep(i,N){ // printf("i=%d\n",i); int X=x[i]; D dval,uval; {//go up D dmx=down.calc(0,X); int mx=-2,arg; rep(j,2){ if(dmx.id[j]!=X){ mx=dmx.mx[j]; arg=dmx.segid[j]; break; } } if(mx>=0){ D dmx2 = down.calc(0,arg) + down.calc(arg+1,X); int mx2=-2,arg2; rep(j,2){ if(dmx2.id[j]!=X){ mx2=dmx2.mx[j]; arg2=dmx2.segid[j]; break; } } dval = D(arg,X,mx,arg2,X,mx2); }else{ dval = D(arg,X,mx,-1,-1,-1); } dval.inc(); dval = dval + D(X); } {//go down D umx=up.calc(X+1,K); int mx=-2,arg; rep(j,2){ if(umx.id[j]!=X){ mx=umx.mx[j]; arg=umx.segid[j]; break; } } if(mx>=0){ D umx2 = up.calc(X+1,arg) + up.calc(arg+1,K); int mx2=-2,arg2; rep(j,2){ if(umx2.id[j]!=X){ mx2=umx2.mx[j]; arg2=umx2.segid[j]; break; } } uval = D(arg,X,mx,arg2,X,mx2); }else{ uval = D(arg,X,mx,-1,-1,-1); } uval.inc(); uval = uval + D(X); } // cout<<"dval"<