Submission #829010

#	Time	Username	Problem	Language	Result	Execution time	Memory
829010		arnold518	Radio Towers (IOI22_towers)	C++17	100 / 100	1100 ms	37944 KiB

towers

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e5;
const int INF = 1e9+7;

int N, A[MAXN+10], B[MAXN+10], P[MAXN+10];
vector<int> comp;

struct SEG
{
	int tree[MAXN*4+10];
	void init(int node, int tl, int tr)
	{
		if(tl==tr)
		{
			tree[node]=A[tl];
			return;
		}
		int mid=tl+tr>>1;
		init(node*2, tl, mid);
		init(node*2+1, mid+1, tr);
		tree[node]=min(tree[node*2], tree[node*2+1]);
	}
	int query(int node, int tl, int tr, int l, int r)
	{
		if(r<tl || tr<l) return INF;
		if(l<=tl && tr<=r) return tree[node];
		int mid=tl+tr>>1;
		return min(query(node*2, tl, mid, l, r), query(node*2+1, mid+1, tr, l, r));
	}
}seg;

struct SEG2
{
	int tree[MAXN*4+10];
	void init(int node, int tl, int tr)
	{
		if(tl==tr)
		{
			tree[node]=P[tl];
			return;
		}
		int mid=tl+tr>>1;
		init(node*2, tl, mid);
		init(node*2+1, mid+1, tr);
		tree[node]=max(tree[node*2], tree[node*2+1]);
	}
	int query1(int node, int tl, int tr, int l, int r, int D)
	{
		if(r<tl || tr<l) return -1;
		if(l<=tl && tr<=r && tree[node]<D) return -1;
		if(tl==tr) return tl;
		int mid=tl+tr>>1;
		int ret=query1(node*2, tl, mid, l, r, D);
		if(ret!=-1) return ret;
		ret=query1(node*2+1, mid+1, tr, l, r, D);
		return ret;
	}
	int query2(int node, int tl, int tr, int l, int r, int D)
	{
		if(r<tl || tr<l) return -1;
		if(l<=tl && tr<=r && tree[node]<D) return -1;
		if(tl==tr) return tl;
		int mid=tl+tr>>1;
		int ret=query2(node*2+1, mid+1, tr, l, r, D);
		if(ret!=-1) return ret;
		ret=query2(node*2, tl, mid, l, r, D);
		return ret;
	}
}seg2;

struct PST
{
	struct Node
	{
		int val, lc, rc;
		Node() : val(0), lc(-1), rc(-1) {}
	};
	vector<Node> NS;
	int tree[MAXN+10];
	
	int newNode()
	{
		NS.push_back(Node());
		return NS.size()-1;
	}

	int makeTree(int tl, int tr)
	{
		int node=newNode();
		if(tl==tr) return node;
		int mid=tl+tr>>1;
		NS[node].lc=makeTree(tl, mid);
		NS[node].rc=makeTree(mid+1, tr);
		return node;
	}

	int addTree(int node, int tl, int tr, int p)
	{
		if(p<tl || tr<p) return node;
		int now=newNode();
		if(tl==tr)
		{
			NS[now].val=NS[node].val+1;
			return now;
		}
		int mid=tl+tr>>1;
		NS[now].lc=addTree(NS[node].lc, tl, mid, p);
		NS[now].rc=addTree(NS[node].rc, mid+1, tr, p);
		NS[now].val=NS[NS[now].lc].val+NS[NS[now].rc].val;
		return now;
	}

	int query(int node, int tl, int tr, int l, int r)
	{
		if(l<=tl && tr<=r) return NS[node].val;
		if(r<tl || tr<l) return 0;
		int mid=tl+tr>>1;
		return query(NS[node].lc, tl, mid, l, r)+query(NS[node].rc, mid+1, tr, l, r);
	}
}pst;

void init(int _N, vector<int> _H)
{
	N=_N;
	for(int i=1; i<=N; i++) A[i]=_H[i-1];
	seg.init(1, 1, N);

	vector<int> V;
	V.push_back(1);
	for(int i=2; i<=N; i++)
	{
		if(V.size()%2)
		{
			if(A[V.back()]<A[i]) V.push_back(i);
			else V.back()=i;
		}
		else
		{
			if(A[V.back()]>A[i]) V.push_back(i);
			else V.back()=i;
		}
	}
	if(V.size()%2==0) V.pop_back();

	set<int> S;
	set<pii> S2;
	for(int i=0; i<V.size(); i++)
	{
		S.insert(V[i]);
		if(i%2==0) B[V[i]]=1;
		else B[V[i]]=2;
	}
	for(int i=0; i+1<V.size(); i++) S2.insert({abs(A[V[i+1]]-A[V[i]]), V[i]});
	
	while(!S2.empty())
	{
		auto [val, p] = *S2.begin(); S2.erase(S2.begin());
		auto it=S.find(p);
		int l=-1, r=-1;

		if(it!=S.begin())
		{
			int t1=*prev(it), t2=*it;
			S2.erase({abs(A[t1]-A[t2]), t1});
			l=t1;
		}
		if(next(next(it))!=S.end())
		{
			int t1=*next(it), t2=*next(next(it));
			S2.erase({abs(A[t1]-A[t2]), t1});
			r=t2;
		}
		if(l!=-1 && r!=-1) S2.insert({abs(A[r]-A[l]), l});

		P[*next(it)]=val; P[*it]=val;
		S.erase(*next(it));
		S.erase(it);
	}

	for(int i=1; i<=N; i++) comp.push_back(P[i]);
	sort(comp.begin(), comp.end());
	comp.erase(unique(comp.begin(), comp.end()), comp.end());

	pst.tree[0]=pst.makeTree(1, comp.size());
	for(int i=1; i<=N; i++) 
	{
		pst.tree[i]=pst.addTree(pst.tree[i-1], 1, comp.size(), lower_bound(comp.begin(), comp.end(), P[i])-comp.begin()+1);
	}

	seg2.init(1, 1, N);
}

int max_towers(int L, int R, int D) 
{
	L++; R++;

	int t=lower_bound(comp.begin(), comp.end(), D)-comp.begin()+1;
	int ans=pst.query(pst.tree[R], 1, comp.size(), t, comp.size())-pst.query(pst.tree[L-1], 1, comp.size(), t, comp.size());
	
	if(!ans) return 1;

	int p=seg2.query1(1, 1, N, L, R, D), q=seg2.query2(1, 1, N, L, R, D);
	if(B[p]==2)
	{
		if(seg.query(1, 1, N, L, p-1)<=A[p]-D) ans++;
		else ans--;
	}
	if(B[q]==2)
	{
		if(seg.query(1, 1, N, q+1, R)<=A[q]-D) ans++;
		else ans--;
	}
	return ans/2+1;
}

Compilation message (stderr)

towers.cpp: In member function 'void SEG::init(int, int, int)':
towers.cpp:25:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'int SEG::query(int, int, int, int, int)':
towers.cpp:34:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   34 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'void SEG2::init(int, int, int)':
towers.cpp:49:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   49 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'int SEG2::query1(int, int, int, int, int, int)':
towers.cpp:59:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   59 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'int SEG2::query2(int, int, int, int, int, int)':
towers.cpp:70:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   70 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'int PST::makeTree(int, int)':
towers.cpp:98:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   98 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'int PST::addTree(int, int, int, int)':
towers.cpp:113:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  113 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In member function 'int PST::query(int, int, int, int, int)':
towers.cpp:124:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  124 |   int mid=tl+tr>>1;
      |           ~~^~~
towers.cpp: In function 'void init(int, std::vector<int>)':
towers.cpp:154:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  154 |  for(int i=0; i<V.size(); i++)
      |               ~^~~~~~~~~
towers.cpp:160:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  160 |  for(int i=0; i+1<V.size(); i++) S2.insert({abs(A[V[i+1]]-A[V[i]]), V[i]});
      |               ~~~^~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 14 / 14
• Subtask 5: 17 / 17
• Subtask 6: 19 / 19
• Subtask 7: 23 / 23