Submission #287953

#	Time	Username	Problem	Language	Result	Execution time	Memory
287953		dvdg6566	Bigger segments (IZhO19_segments)	C++14	73 / 100	605 ms	262148 KiB

segments

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pi;
typedef vector<ll> vi;
typedef vector<pi> vpi;
typedef long double ld;
#define pb emplace_back
#define mp make_pair
#define f first
#define s second
#define SZ(x) (ll)x.size()
#define ALL(x) x.begin(),x.end()
#define lb lower_bound
#define ub upper_bound
const ll MAXN=500001;
const ll MOD=1e9+7;
const ll INF = 3e9;

ll A[MAXN];
ll N;
ll dp[MAXN];
ll S[MAXN];

struct node{
	ll s,e,m;
	node *l,*r;
	pi v;
	node(ll _s,ll _e):s(_s),e(_e){
		m=(s+e)/2;
		v=mp(0,0);
		l=r=nullptr;
	}
	pi ask(ll x,ll y){
		assert(s<=x&&y<=e);
		if(s==x&&e==y)return v;
		pi t=mp(0,0);
		if(l&&x<=m)t=max(t, l->ask(x,min(y,m)));
		if(r&&y>m)t=max(t,r->ask(max(m+1,x),y));
		return t;
	}
	void up(ll x,pi va){
		assert(s<=x&&x<=e);
		if(s==e){v=max(v,va);return;}
		if(x<=m){
			if(!l)l=new node(s,m);
			l->up(x,va);
		}else{
			if(!r)r=new node(m+1,e);
			r->up(x,va);
		}
		v=mp(0,0);
		if(l)v=max(v,l->v);
		if(r)v=max(v,r->v);
	}
}*root;

int main(){
	cin>>N;
	for(int i=1;i<=N;++i){
		cin>>A[i];
		A[i]+=A[i-1];
	}
	root=new node(0,2*A[N]);
	root->up(0,mp(0,0));
	for(int i=1;i<=N;++i){
		pi x=root->ask(0,A[i]);
		// cerr<<x.f<<' '<<x.s<<'\n';
		ll p=x.s;
		dp[i]=x.f+1;
		root->up(2*A[i]-A[p], mp(dp[i],i));
		// for(int j=1;j<=i;++j){
		// 	// take from i to j
		// 	// cerr<<i<<' '<<j<<' '<<x<<'\n';
		// 	if(x >= S[j-1]){
		// 		if(dp[j-1]+1 >= dp[i]){
		// 			dp[i]=dp[j-1]+1;
		// 			S[i] = x+A[i]-A[j-1];
		// 		}
		// 	}
		// }
		// cerr<<i<<' '<<dp[i]<<' '<<S[i]<<'\n';
	}
	cout<<dp[N];
}

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 0 / 27