Submission #123204

#	Time	Username	Problem	Language	Result	Execution time	Memory
123204		SirCeness	Ancient Books (IOI17_books)	C++14	50 / 100	878 ms	166228 KiB

books

#include <bits/stdc++.h>

#define pb push_back
#define mp make_pair
#define inside sl<=l&&r<=sr
#define outside r<sl||sr<l
#define inf 1000000009
using namespace std;
typedef long long ll;

int n;
vector<int> arr;
vector<ll> numara;
vector<ll> beg;
vector<ll> en;
vector<ll> djkdist;
vector<pair<int, pair<int, int> > > edges;
list<pair<int, int> > adj[1000006];
int num = 0;
vector<pair<ll, ll> > minler;
vector<int> dsu;

int find(int node){
	if (dsu[node] == node) return node;
	int ans = find(dsu[node]);
	return dsu[node] = ans;
}

void unionn(int node1, int node2){
	node1 = find(node1);
	node2 = find(node2);
	if (node1 == node2) return;
	dsu[node1] = node2;
}

void djk(int source, int size){
	priority_queue<pair<int, int> > qu;
	qu.push(mp(0, source));
	
	djkdist.resize(size);
	for (int i = 0; i < djkdist.size(); i++) djkdist[i] = -1;
	while (!qu.empty()){
		int node = qu.top().second;
		ll w = -qu.top().first;
		qu.pop();
		if (djkdist[node] != -1) continue;
		djkdist[node] = w;
		for (list<pair<int, int> >::iterator it = adj[node].begin(); it != adj[node].end(); ++it){
			if (djkdist[it -> first] != -1) continue;
			qu.push(mp(-w-it -> second, it -> first));
		}
	}
}

ll minimum_walk(vector<int> p, int s){
	arr = p;
	n = p.size();
	numara.resize(n);
	int sonn = n-1;
	while (p[sonn] == sonn && sonn > 0) sonn--;
	if (sonn == 0) return 0;
	int strt = 0;
	while (p[strt] == strt) strt++;
	ll ans = 0;
	for (int i = 0; i < n; i++) numara[i] = -1;
	for (int i = 0; i < n; i++){
		if (numara[i] == -1 && p[i] != i){
			int node = i;
			int lmost = node;
			int rmost = node;
			while (numara[node] == -1){
				numara[node] = num;
				ans += abs(p[node] - node);
				node = p[node];
				lmost = min(lmost, node);
				rmost = max(rmost, node);
			}
			beg.pb(lmost);
			en.pb(rmost);
			num++;
		}
	}
	
	//for (int i = 0; i < n; i++) cout << numara[i] << " "; cout << endl;
	
	int last = -1;
	for (int i = 0; i < n; i++){
		if (numara[i] != -1){
			if (last != -1){
				//cout << "edge: " << numara[i] << " - " << numara[last] << " -> " << abs(last-i) << endl;
				adj[numara[i]].pb(mp(numara[last], abs(last-i)));
				adj[numara[last]].pb(mp(numara[i], abs(last-i)));
			}
			last = i;
		}
	}
	
	vector<list<int> > begs(n);
	vector<list<int> > ens(n);
	for (int i = 0; i < num; i++){
		begs[beg[i]].pb(i);
		ens[en[i]].pb(i);
	}
	set<int> open;
	int flag = 1;
	vector<int> trumu(num);
	for (int i = 0; i < num; i++) trumu[i] = 0;
	for (int i = strt; i <= sonn; i++){
		for (list<int>::iterator it = begs[i].begin(); it != begs[i].end(); ++it){
			if (open.size() == 0) trumu[*it] = 1;
			open.insert(*it);
		}
		int foo = 0;
		for (list<int>::iterator it = ens[i].begin(); it != ens[i].end(); ++it){
			//assert(open.find(*it) != open.end());
			open.erase(open.find(*it));
			if (trumu[*it] == 1) foo = 1;
		}
		if (open.size() == 0) ans += 2;
		if (i == s && open.size() == 0){
			flag = 0;
		}
		if (foo){
			for (set<int>::iterator it = open.begin(); it != open.end(); ++it){
				trumu[*it] = 1;
			}
		}
	}
	ans -= 2;
	
	ll mindist = inf;
	for (int i = s; i < n; i++){
		if (numara[i] != -1){
			djk(numara[i], num);
			for (int j = 0; j < num; j++){
				if (trumu[j] == 0) continue;
				mindist = min(mindist, abs(i-s) + djkdist[j]);
			}
			break;
		}
	}
	for (int i = s; i >= 0; i--){
		if (numara[i] != -1){
			djk(numara[i], num);
			for (int j = 0; j < num; j++){
				if (trumu[j] == 0) continue;
				mindist = min(mindist, abs(i-s) + djkdist[j]);
			}
			break;
		}
	}
	
	ans += 2*mindist;
	
	/*cout << "trumu: ";
	for (int i = 0; i < num; i++) cout << trumu[i] << " "; cout << endl;
	
	cout << "sonn: " << sonn << endl;
	cout << "strt: " << strt << endl;
	cout << "mindist: " << mindist << endl;*/
	
	return ans;
}

Compilation message (stderr)

books.cpp: In function 'void djk(int, int)':
books.cpp:41:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < djkdist.size(); i++) djkdist[i] = -1;
                  ~~^~~~~~~~~~~~~~~~
books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:105:6: warning: variable 'flag' set but not used [-Wunused-but-set-variable]
  int flag = 1;
      ^~~~

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