Submission #756632

#	Time	Username	Problem	Language	Result	Execution time	Memory
756632		jamezzz	Tortoise (CEOI21_tortoise)	C++17	0 / 100	7 ms	11988 KiB

tortoise

#include <bits/stdc++.h>
using namespace std;

#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
#define INF 1023456789
#define LINF 1023456789123456789
#define lb(x,v) lower_bound(all(x),v)-x.begin()
#define disc(x) sort(all(x)),x.resize(unique(all(x))-x.begin())
typedef long long ll;
typedef pair<int,int> ii;
typedef pair<ll,int> li;

#define maxn 500005

struct node{
	int s,e,m,lz;ii v;
	node *l,*r;
	node(int _s,int _e){
		s=_s,e=_e,m=(s+e)>>1,lz=0;v={1,s};
		if(s!=e)l=new node(s,m),r=new node(m+1,e);
	}
	void ppo(){
		v.se+=lz;
		if(s!=e)l->lz+=lz,r->lz+=lz;
		lz=0;
	}
	void add(int x,int y,int nv){
		if(s==x&&e==y){lz+=nv;return;}
		if(y<=m)l->add(x,y,nv);
		else if(x>m)r->add(x,y,nv);
		else l->add(x,m,nv),r->add(m+1,y,nv);
		l->ppo(),r->ppo();
		v=min(l->v,r->v);
	}
	inline void flip(int x){
		if(s==x&&e==x){v.fi=1-v.fi;return;}
		if(x<=m)l->flip(x);
		else r->flip(x);
		l->ppo(),r->ppo();
		v=min(l->v,r->v);
	}
	ii qry(int x,int y){
		ppo();
		if(s==x&&e==y)return v;
		if(y<=m)return l->qry(x,y);
		else if(x>m)return r->qry(x,y);
		else return min(l->qry(x,m),r->qry(m+1,y));
	}
}*rt;

int n,a[maxn],l[maxn],r[maxn],pos[maxn];
vector<ii> cyc[maxn],stuff;

int dbg=0;

int main(){
	sf("%d",&n);
	for(int i=0;i<n;++i)sf("%d",&a[i]);
	l[0]=(a[0]==-1)?0:-1;
	for(int i=1;i<n;++i){
		if(a[i]==-1)l[i]=i;
		else l[i]=l[i-1];
	}
	r[n-1]=(a[n-1]==-1)?n-1:n;
	for(int i=n-2;i>=0;--i){
		if(a[i]==-1)r[i]=i;
		else r[i]=r[i+1];
	}
	for(int i=0;i<n;++i){
		if(a[i]>0){
			int d=(r[i]==n?INF:r[i])-i;
			if(l[i]!=-1)d=min(d,i-l[i]);
			cyc[r[i]].pb({d,i});
		}
	}
	rt=new node(0,n-1);
	for(int i=0;i<=n;++i){
		if(cyc[i].empty())continue;
		sort(all(cyc[i]));
		int x=cyc[i].back().se;
		--a[x];
		pos[r[i]]=x;
		//need to reach here at x time
		rt->flip(x);
		if(dbg)pf("walk: %d\n",x);
	}
	for(int i=0;i<n;++i){
		if(a[i]>0){
			int d=INF;
			if(l[i]!=-1)d=min(d,i-l[i]);
			d=min(d,(r[i]==n?INF:r[i])-i);
			stuff.pb({d,i});
		}
	}
	sort(all(stuff));
	for(auto[d,i]:stuff){
		int num=a[i];
		ii mn=rt->qry(i,n-1);
		if(mn.fi!=1)min(a[i],mn.se/(2*d));
		if(dbg)pf("d: %d\n",d);
		if(dbg)pf("mn: %d %d\n",mn.fi,mn.se);
		int rem=rt->qry(i,i).se;
		int cur=rem/(2*d);
		if(i<pos[r[i]]&&rem%(2*d)>=d)++cur;
		if(dbg)pf("rem %d, cur %d\n",rem,cur);
		num=min(num,cur);
		if(dbg)pf("take %d of %d\n\n",num,i);
		a[i]-=num;
		if(num>0){
			rt->flip(i);
			rt->add(i,n-1,-num*d*2);
		}
	}
	ll ans=0;
	for(int i=0;i<n;++i){
		if(a[i]>0)ans+=a[i];
	}
	pf("%lld\n",ans);
}

/*
5
-1 1 1 1 1

2

8
-1 1 0 0 -1 0 0 3

1

8
2 -1 2 -1 2 -1 2 -1

1
*/

Compilation message (stderr)

tortoise.cpp: In function 'int main()':
tortoise.cpp:63:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |  sf("%d",&n);
      |    ^
tortoise.cpp:64:24: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |  for(int i=0;i<n;++i)sf("%d",&a[i]);
      |                        ^

• Subtask 1: 0 / 8
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 25
• Subtask 5: 0 / 27