Submission #807736

#TimeUsernameProblemLanguageResultExecution timeMemory
807736I_Love_EliskaM_Comparing Plants (IOI20_plants)C++17
60 / 100
728 ms51168 KiB
#include "plants.h"
#include <bits/stdc++.h>
using namespace std;
#define forn(i,_n) for(int i=0;i<_n;++i)
#define all(x) x.begin(),x.end()
#define pb push_back
#define pi pair<int,int>
#define f first
#define s second
using ll = long long;

const int N=2e5+55;
int p[N], L[N], R[N];
int n;
int k;

struct sgt {
	vector<pi> t;
	vector<int> lazy; 
	int sz=1;
	pi merge(pi a, pi b) {
		if (a.f > b.f) return a;
		return b;
	}
	sgt(int n) {
		while (sz<n) sz<<=1;
		t.assign(2*sz,{0,n});
		forn(i,n) t[sz-1+i]={0,i};
		lazy.assign(4*sz,0);
	}
	void push(int v) {
		t[v].f+=lazy[v];
		lazy[2*v+1]+=lazy[v];
		lazy[2*v+2]+=lazy[v];
		lazy[v]=0;
	}
	void add(int v, int l, int r, int lx, int rx, int x) {
		if (lazy[v]) push(v);
		if (rx<=l || r<=lx) return;
		if (lx<=l && r<=rx) {
			lazy[v]+=x;
			push(v);
			return;
		}
		int m=(l+r)>>1;
		add(2*v+1,l,m,lx,rx,x);
		add(2*v+2,m,r,lx,rx,x);
		t[v]=merge(t[2*v+1],t[2*v+2]);
	}
	void add(int l, int r, int x) {
		add(0,0,sz,l,r,x);
	}
	pi query(int v, int l, int r, int lx, int rx) {
		if (lazy[v]) push(v);
		if (rx<=l || r<=lx) return {-2e9,n};
		if (lx<=l && r<=rx) return t[v];
		int m=(l+r)>>1;
		auto lq=query(2*v+1,l,m,lx,rx);
		auto rq=query(2*v+2,m,r,lx,rx);
		t[v]=merge(t[2*v+1],t[2*v+2]);
		return merge(lq,rq);
	}
	pi query(int l, int r) {
		return query(0,0,sz,l,r);
	}
};
sgt st(N);

vector<int> adj[305];
int vis[305];
bitset<305> bs[305];

void dfs(int u) {
	if (vis[u]==1) assert(0);
	if (vis[u]) return;
	bs[u][u]=1;
	vis[u]=1;
	for(auto&v:adj[u]) {
		dfs(v);
		bs[u]|=bs[v];
	}
	vis[u]=2;
}

void init(int _k, vector<int> r) {
	k=_k;
	n=r.size();

	if (n<=300) {
		forn(i,n) r[i]=k-1-r[i];
		forn(i,n) r.pb(r[i]);
		forn(i,n) r.pb(r[i]);
		forn(it,n) {
			for (int i=n; i<2*n; ++i) {
				if (r[i]==k-1) {
					int z=i;
					for (int j=i; j>z-k; --j) if (r[j]==k-1) z=j;
					for (int j=z+1; j<z+k; ++j) {
						if (vis[j%n]) adj[j%n].pb(z%n);
						else adj[z%n].pb(j%n);
					}
					vis[z%n]=1;
					r[z%n]=-1e9;
					for (int j=z; j>z-k; --j) {
						r[(j%n)]++;
						r[(j%n)+n]++;
						r[(j%n)+2*n]++;
					}
					break;
				}
			}
		}
		forn(i,n) vis[i]=0;
		forn(i,n) dfs(i);
		return;
	}

	if (k==2) {
		int z=0;
		forn(i,n) r[i]^=1;
		forn(i,n) if (r[i]==0) z=i;
		for (int i=z+n; i>z; --i) {
			if (r[i%n]) R[i%n]=R[(i+1)%n];
			else R[i%n]=i%n;
		}
		z=0;
		forn(i,n) if (r[i]) z=i;
		++z;
		for (int i=z; i<z+n; ++i) {
			if (r[(i-1+n)%n]) L[i%n]=i%n;
			else L[i%n]=L[(i-1+n)%n];
		}
		forn(i,n) {
			L[i]+=n, R[i]+=n;
		}
		forn(i,n) {
			if (L[i]==R[i] && L[i]==i+n) continue;
			if (L[i]>=R[i]) L[i]-=n;
		}
		return;
	}

	forn(i,n) r.pb(r[i]);
	forn(i,n) r.pb(r[i]);

	sgt st(n);
	forn(i,n) st.add(i,i+1,r[i]);

	int z;
	for (int i=n; i<2*n; ++i) {
		if (r[i]==k-1) {
			z=i;
			for (int j=i; j>z-k; --j) if (r[j]==k-1) z=j;
			break;
		}
	}

	set<int> s;
	set<int> ok;
	int ri=-1;
	for (int l=z; l<z+n; ++l) {
		if (r[l]==k-1) {
			s.insert(l%n);
			s.insert(l%n+n);
			s.insert(l%n+2*n);
			if (l>=ri) {
				ok.insert(l%n);
			}
			ri=l+k;
		}
	}

	int nxt=1;
	forn(it,n) {
		auto x=*ok.begin(); ok.erase(ok.begin());
		
		p[x]=nxt++;

		s.erase(x);
		s.erase(x+n);
		s.erase(x+2*n);
		st.add(x,x+1,-1e9);
		int j=x;
		if (s.size()) {
			auto it1=s.lower_bound(x);
			j=*it1;
		}
		j%=n;

		if (x-k+1>=0) {
			st.add(x-k+1,x,1);
		} else {
			st.add(0,x,1);
			st.add(x-k+1+n,n,1);
		}
		vector<int> v;
		while(1) {
			pi q;
			if (x-k+1>=0) {
				q=st.query(x-k+1,x);
			} else {
				auto q1=st.query(0,x);
				auto q2=st.query(x-k+1+n,n);
				q=st.merge(q1,q2);
			}
			if (q.f<k-1) break;
			if (q.s > j) {
				j+=n;
			}
			if (j-q.s>=k) {
				ok.insert(j%n);
			}
			j=q.s;
			s.insert(j);
			s.insert(j+n);
			s.insert(j+2*n);
			st.add(j,j+1,-1e9);
			v.pb(j);
		}
		if (!s.size()) break;
		for(auto&x:v) st.add(x,x+1,1e9);
		auto it2 = s.find(j+n);
		--it2;
		int t = *it2;
		if (j+n-t>=k) ok.insert(j);
	}

}

int compare_plants(int x, int y) {
	if (n<=300) {
		if (bs[x][y]) {
			return 1;
		}
		if (bs[y][x]) {
			return -1;
		}
		return 0;
	}
	if (k==2) {
		if (L[x]<=y && y<=R[x]) return 1;
		if (L[x]<=y+n && y+n<=R[x]) return 1;
		swap(x,y);
		if (L[x]<=y && y<=R[x]) return -1;
		if (L[x]<=y+n && y+n<=R[x]) return -1;
		return 0;
	}
	if (p[x]>p[y]) return 1;
	else return -1;
}

Compilation message (stderr)

plants.cpp: In function 'void init(int, std::vector<int>)':
plants.cpp:161:19: warning: 'z' may be used uninitialized in this function [-Wmaybe-uninitialized]
  161 |  for (int l=z; l<z+n; ++l) {
      |                  ~^~
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