Submission #137710

#	Time	Username	Problem	Language	Result	Execution time	Memory
137710		MAMBA	Ancient Books (IOI17_books)	C++17	50 / 100	253 ms	21736 KiB

books

#include "books.h"
#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define rep(i , j , k) for(int i = j; i < (int)k; i++)

typedef long long ll;

const int N = 1e6 + 10;

int par[N];
ll le[N], ri[N], arr[N];

int getPar(int v) {
	return v == par[v] ? v : par[v] = getPar(par[v]); 
}

inline bool merge(int u , int v) {
	if ((u = getPar(u)) == (v = getPar(v))) 
		return false;
	par[v] = u;
	return true;
}

inline void smax(ll &a, ll b) {
	if (a < b) a = b;
}

inline void smin(ll &a, ll b) {
	if (b < a) a = b;
}



long long minimum_walk(std::vector<int> p, int s) {

	int n = p.size();

	iota(par , par + n , 0);


	vector<int> vp(n);
	ll res = 0;
	rep(i , 0 , n) {
		res += abs(p[i] - i);
		merge(i , p[i]);
		vp[min(i , p[i])] = max(vp[min(i , p[i])] ,  max(i , p[i]));
	}

	int G = -1;

	rep(i , 0 , n) {
		if (G >= i && i != s)
			merge(i , i - 1);
		G = max(G , vp[i]);
	}

	int last = -1;

	vector<pair<ll , pair<int , int>>> vec;
	rep(i , 0 , n) {
		if (i == p[i] && i != s) continue;
		if (last == -1 || getPar(last) == getPar(i))
			last = i;
		else {
			vec.pb({2 * (i - last) , {last , i}});
			last = i;
		}
	}

	sort(vec.begin(), vec.end());

	for (auto e : vec)
		if (merge(e.second.first , e.second.second))
			res += e.first;
	return res;

}

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