Submission #1048566

#	Time	Username	Problem	Language	Result	Execution time	Memory
1048566		LittleOrange	Ancient Books (IOI17_books)	C++17	50 / 100	107 ms	94496 KiB

books

#include "books.h"
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll big = 1e18;
struct obj{
	ll i,w;
	bool operator<(const obj &o)const{
		return w>o.w;
	}
};
struct BIT{
	ll n;
	vector<ll> a;
	BIT(ll N):n(N),a(N+5,0){}
	void add(ll i, ll v){
		for(;i<=n;i+=i&-i) a[i] += v;
	}
	ll get(ll i){
		ll v = 0;
		for(;i>0;i-=i&-i) v += a[i];
		return v;
	}
};
struct segtree{
	ll n;
	vector<ll> a;
	segtree(ll N):n(N),a(N<<2,big){}
	void mod(ll i, ll l, ll r, ll ql, ll qr, ll x){
		if(ql<=l&&r<=qr) a[i] = min(a[i],x);
		else{
			ll m = l+r>>1;
			if(ql<=m) mod(i<<1,l,m,ql,qr,x);
			if(qr>m) mod(i<<1|1,m+1,r,ql,qr,x);
		}
	}
	ll get(ll i, ll l, ll r, ll x){
		if (l == r) return a[i];
		else{
			ll m = l+r>>1;
			if (x<=m) return min(a[i],get(i<<1,l,m,x));
			else return min(a[i],get(i<<1|1,m+1,r,x));
		}
	}
};
long long minimum_walk(std::vector<int> p, int s) {
	ll ans = 0;
	ll n = p.size();
	ll gpc = 0;
	vector<ll> gp(n,-1);
	vector<ll> L,R;
	vector<vector<ll>> gps;
	for(ll i = 0;i<n;i++){
		if (gp[i]==-1){
			ll cur = gpc++;
			gps.emplace_back();
			L.push_back(n);
			R.push_back(0);
			ll x = i;
			do{
				L[cur] = min(x,L[cur]);
				R[cur] = max(x,R[cur]);
				gp[x] = cur;
				gps[cur].push_back(x);
				ans += abs(p[x]-x);
				x = p[x];
			} while(x!=i);
		}
	}
	vector<ll> v(n,0);
	for(ll i : L) v[i]++;
	for(ll i : R) v[i]--;
	for(ll i = 1;i<n;i++) v[i] += v[i-1];
	ll rf = n-1;
	while(rf&&p[rf]==rf) rf--;
	for(ll i = 0;i<rf;i++) if(!v[i]) ans += 2;
	ll cL = s, cR = s;
	for(ll i : L) if(i<=s) cL=min(cL,i);
	for(ll i : R) if(i>=s) cR=max(cR,i);
	/*
	vector<ll> dis(n,n);
	segtree t(n);
	priority_queue<obj> q;
	q.push({s,0});
	while(!q.empty()){
		auto [i,w] = q.top();q.pop();
		w = min(w,t.get(1,0,n-1,i));
		if (dis[i]<=w) continue;
		dis[i] = w;
		q.push({L[gp[i]],w});
		q.push({R[gp[i]],w});
		t.mod(1,0,n-1,L[gp[i]],R[gp[i]],w);
		if(i>0) q.push({i-1,w+1});
		if(i<n-1) q.push({i+1,w+1});
	}
	ans += min(dis[cL],dis[cR])*2;*/
	if (s!=0&&n<=1000){
		ll m = gpc;
		vector<vector<ll>> con(m,vector<ll>(m,n));
		for(ll i = 0;i<m;i++){
			for(ll j = 0;j<m;j++){
				for(ll x : gps[j]){
					for(ll y : gps[i]){
						con[i][j] = min(con[i][j],abs(x-y));
					}
					if(L[i]<=x&&x<=R[i]) con[i][j] = 0;
				}
			}
		}
		for(ll i = 0;i<m;i++){
			for(ll j = i;j<m;j++){
				ll o = con[i][j]+con[j][i];
				con[i][j] = con[j][i] = o;
			}
		}
		vector<ll> dis(m,n);
		priority_queue<obj> q;
		q.push({gp[s],0});
		while(!q.empty()){
			auto [i,w] = q.top();q.pop();
			if(dis[i]<=w) continue;
			dis[i] = w;
			for(ll j = 0;j<m;j++){
				q.push({j,w+con[i][j]});
			}
		}
		ll add = min(dis[gp[cL]],dis[gp[cR]]);
		ans += add;
	}
	return ans;
}

Compilation message (stderr)

books.cpp: In member function 'void segtree::mod(ll, ll, ll, ll, ll, ll)':
books.cpp:32:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   32 |    ll m = l+r>>1;
      |           ~^~
books.cpp: In member function 'll segtree::get(ll, ll, ll, ll)':
books.cpp:40:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   40 |    ll m = l+r>>1;
      |           ~^~

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