Submission #384960

#	Time	Username	Problem	Language	Result	Execution time	Memory
384960		kshitij_sodani	Ancient Books (IOI17_books)	C++14	70 / 100	1627 ms	286680 KiB

books

//#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
typedef long long llo;
#define mp make_pair
#define pb push_back
#define a first 
#define b second
#define endl '\n'


#include "books.h"
int ans=0;
int n;
vector<int> adj[1000001];
int vis[1000001];
//pair<int,int> cot[1000001];
int par[1000001];
/*int find(int no){
	if(par[no]==no){
		return no;
	}
	par[no]=find(par[no]);
	return par[no];
}*/
vector<int> ss;
void dfs(int no){
	vis[no]=1;
	ss.pb(no);
	for(auto j:adj[no]){
		if(vis[j]==0){
			dfs(j);
		}
	}
}


//vector<int> adj2[1000001];
int ind[1000001];
pair<int,int> pp;
vector<pair<int,int>> tt;
vector<pair<int,int>> pre2[1000001];

vector<pair<int,int>> pre3[1000001];

//int dp[1001][1001];
pair<int,int> rr2[1000001];

pair<int,int> rr[1000001];

/*void dfs2(int no,int par=-1){
	pp.a=min(pp.a,tt[no].a);
	pp.b=max(pp.b,tt[no].b);
	vis[no]=1;
	for(auto j:adj2[no]){
		if(vis[j]==0){
			dfs2(j);
		}
	}
}*/
vector<int> kk[1000001];
int tree[4*1000001];
void update(int no,int l,int r,int i,int j){
	if(l==r){
		tree[no]=min(tree[no],j);
	}
	else{
		int mid=(l+r)/2;
		if(i<=mid){
			update(no*2+1,l,mid,i,j);
		}
		else{
			update(no*2+2,mid+1,r,i,j);
		}
		tree[no]=min(tree[no*2+1],tree[no*2+2]);
	}
}
int query(int no,int l,int r,int aa,int bb){
	if(r<aa or l>bb){
		return n;
	}
	if(aa<=l and r<=bb){
		return tree[no];
	}
	else{
		int mid=(l+r)/2;
		return min(query(no*2+1,l,mid,aa,bb),query(no*2+2,mid+1,r,aa,bb));
	}
}

int tree2[4*1000001];
void update2(int no,int l,int r,int i,int j){
	if(l==r){
		tree2[no]=max(tree2[no],j);
	}
	else{
		int mid=(l+r)/2;
		if(i<=mid){
			update2(no*2+1,l,mid,i,j);
		}
		else{
			update2(no*2+2,mid+1,r,i,j);
		}
		tree2[no]=max(tree2[no*2+1],tree2[no*2+2]);
	}
}
int query2(int no,int l,int r,int aa,int bb){
	if(r<aa or l>bb){
		return 0;
	}
	if(aa<=l and r<=bb){
		return tree2[no];
	}
	else{
		int mid=(l+r)/2;
		return max(query2(no*2+1,l,mid,aa,bb),query2(no*2+2,mid+1,r,aa,bb));
	}
}

long long minimum_walk(std::vector<int> p, int s) {
	while(p.size()){
		if(p.back()+1==p.size()){
			p.pop_back();
		}
		else{
			break;
		}
	}
	n=p.size();
	if(n==0){
		return 0;
	}
	for(int i=0;i<n;i++){
		adj[i].pb(p[i]);
	}
	//int co=0;
	llo ans=0;
	vector<vector<int>> zz5;
	for(int i=0;i<n;i++){
		if(vis[i]==0){
			ss.clear();
			dfs(i);

			int mi=ss[0];
			int ma=ss[0];
			for(auto j:ss){
				mi=min(mi,j);
				ma=max(ma,j);
			}
			/*for(auto j:ss){
				cot[j]={mi,ma};
			}*/
			int zz=tt.size();
			for(auto j:ss){
				ind[j]=tt.size();
			}
			rr2[tt.size()]={mi,ma};
			tt.pb({mi,ma});
			
			for(int j=0;j+1<ss.size();j++){
				ans+=(llo)abs(ss[j]-ss[j+1]);
			}
			zz5.pb(ss);

			ans+=(llo)(abs(ss[0]-ss.back()));
			sort(ss.begin(),ss.end());
			for(int j=0;j+1<ss.size();j++){
				pre2[ss[j+1]].pb({ss[j],zz});
			}
			for(int j=0;j+1<ss.size();j++){
				pre3[ss[j]].pb({ss[j+1],zz});
			}
		}
	}

	for(int i=0;i<4*n;i++){
		tree[i]=4*n;
	}
	for(int i=0;i<n;i++){
		for(auto j:pre2[i]){
			int x=query(0,0,n-1,j.a,i-1);
			rr2[j.b].a=min(rr2[j.b].a,x);
			update(0,0,n-1,i,rr2[j.b].a);

		}
	}
	for(int i=0;i<4*n;i++){
		tree2[i]=0;
	}
	for(int i=n-1;i>=0;i--){
		for(auto j:pre3[i]){
			int x=query2(0,0,n-1,i+1,j.a);
			rr2[j.b].b=max(rr2[j.b].b,x);
			update2(0,0,n-1,i,rr2[j.b].b);

		}
	}	
	for(int i=0;i<tt.size();i++){
		for(auto j:zz5[i]){
			rr[j]=rr2[i];
		}
	}


	pair<int,int> cur3={rr[s].a,rr[s].b};
	while(cur3.a>0 or cur3.b<n-1){
		if(cur3.b==n-1){
			ans+=2;
			cur3={rr[cur3.a-1].a,max(cur3.b,rr[cur3.a-1].b)};
			continue;
		}
		else if(cur3.a==0){
			ans+=2;
			cur3={min(rr[cur3.b+1].a,cur3.a),rr[cur3.b+1].b};
			continue;
		}
		else{

			
			if(rr[cur3.a-1].b>cur3.b){
				ans+=2;

				cur3={rr[cur3.a-1].a,max(cur3.b,rr[cur3.a-1].b)};
				continue;
			}
			else if(rr[cur3.b+1].a<cur3.a){
				ans+=2;
				cur3={min(rr[cur3.b+1].a,cur3.a),rr[cur3.b+1].b};
				continue;
			}
			vector<pair<int,int>> aa;
			vector<pair<int,int>> bb;
			pair<int,int> cur4=cur3;
			pair<int,int> cur5=cur3;
			int st=0;
			while(cur4.a>0 or cur5.b<n-1){
				if(cur4.a>0){
					if(rr[cur4.a-1].b>cur3.b){
						st=0;
						break;
					}
				}
				if(cur5.b<n-1){
					if(rr[cur5.b+1].a<cur3.a){
						st=1;
						break;
					}
				}
				if(cur5.b==n-1){
					st=1;
					break;
				}
				if(cur4.a==0){
					st=0;
					break;
				}
				cur4={rr[cur4.a-1].a,max(cur4.b,rr[cur4.a-1].b)};
				aa.pb(cur4);
				cur5={min(rr[cur5.b+1].a,cur5.a),rr[cur5.b+1].b};
				bb.pb(cur5);
			}
			/*if(cur5.b==n-1){
				st=1;
			}*/
			
			/*while(cur5.b<n-1){
				
			}*/
			if(st==0){
				cur3=aa.back();
				ans+=(llo)(2*aa.size());
			}
			else{
				cur3=bb.back();
				ans+=(llo)(2*bb.size());
			}
			
			//cur3={rr[cur3.a-1].a,max(cur3.b,rr[cur3.a-1].b)};
		}
	}






	return ans;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:122:16: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  122 |   if(p.back()+1==p.size()){
      |      ~~~~~~~~~~^~~~~~~~~~
books.cpp:160:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  160 |    for(int j=0;j+1<ss.size();j++){
      |                ~~~^~~~~~~~~~
books.cpp:167:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  167 |    for(int j=0;j+1<ss.size();j++){
      |                ~~~^~~~~~~~~~
books.cpp:170:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  170 |    for(int j=0;j+1<ss.size();j++){
      |                ~~~^~~~~~~~~~
books.cpp:198:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  198 |  for(int i=0;i<tt.size();i++){
      |              ~^~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 20 / 20
• Subtask 5: 0 / 30