Submission #1048488

#	Time	Username	Problem	Language	Result	Execution time	Memory
1048488		LittleOrange	Ancient Books (IOI17_books)	C++17	50 / 100	266 ms	103832 KiB

books

#include "books.h"
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
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;
	}
};
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);
	priority_queue<obj> q;
	q.push({s,0});
	while(!q.empty()){
		auto [i,w] = q.top();q.pop();
		if (dis[i]<=w) continue;
		dis[i] = w;
		q.push({L[gp[i]],w});
		q.push({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;
	return ans;
}

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