제출 #292955

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
292955		Kastanda	고대 책들 (IOI17_books)	C++11	50 / 100	565 ms	73068 KiB

books

// M
#include<bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long ll;
const int N = 1000006;
int n, st, P[N], A[N], mn[N], mx[N];
int Find(int v)
{
        return (P[v] < 0 ? v : (P[v] = Find(P[v])));
}
inline void Merge(int v, int u)
{
        v = Find(v);
        u = Find(u);
        if (v == u)
                return ;
        P[u] = v;
        mn[v] = min(mn[v], mn[u]);
        mx[v] = max(mx[v], mx[u]);
}

long long minimum_walk(vector < int > _A, int _st)
{
        n = (int)_A.size();
        st = _st + 1;
        for (int i = 1; i <= n; i ++)
                A[i] = _A[i - 1] + 1;

        ll SM = 0, tot = 0;
        for (int i = 1; i <= n; i ++)
                SM += abs(A[i] - i);
        memset(P, -1, sizeof(P));
        for (int i = 1; i <= n; i ++)
                mn[i] = mx[i] = i;
        set < int > ST;
        for (int i = 1; i <= n; i ++)
                ST.insert(i);

        for (int i = 1; i <= n; i ++)
                if (i != A[i])
                {
                        int l = min(i, A[i]);
                        int r = max(i, A[i]);
                        auto it = ST.lower_bound(l);
                        while (it != ST.end() && * it < r)
                                Merge(* it, (* it) + 1), it = ST.erase(it);
                }
        vector < pair < int , int > > vec;
        for (int i = 1; i <= n; i ++)
                if (Find(i) == i && i != A[i])
                        vec.push_back({mn[i], mx[i]});
        sort(vec.begin(), vec.end());
        while (vec.size() > 1 && vec[(int)vec.size() - 2].second >= st)
                tot += vec.back().first - vec[(int)vec.size() - 2].second, vec.pop_back();
        if (vec.size() && vec.back().first >= st)
                tot += vec.back().first - st, vec.pop_back();
        reverse(vec.begin(), vec.end());
        while (vec.size() > 1 && vec[(int)vec.size() - 2].first <= st)
                tot += vec[(int)vec.size() - 2].first - vec.back().second, vec.pop_back();
        if (vec.size() && vec.back().second <= st)
                tot += st - vec.back().second, vec.pop_back();
        if (vec.size())
        {
                assert(vec.size() == 1 && vec[0].first <= st && st <= vec[0].second);
                if (A[st] == st)
                {
                        int l = st;
                        while (l && A[l] == l)
                                l --;
                        assert(l >= vec[0].first);
                        int Best = st - l;
                        int r = st;
                        while (r <= n && A[r] == r)
                                r ++;
                        assert(r <= vec[0].second);
                        Best = min(Best, r - st);
                        tot += Best;
                }
        }

        tot = tot * 2 + SM;
        return tot;
}

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