Submission #290680

#	Time	Username	Problem	Language	Result	Execution time	Memory
290680		SamAnd	Ancient Books (IOI17_books)	C++17	22 / 100	161 ms	16248 KiB

books

#include "books.h"
#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
typedef long long ll;
const int N = 1003;

int n;

int bfs(vector<int> p, int s)
{
    for (int i = 0; i < n; ++i)
        ++p[i];
    map<pair<vector<int>, pair<int, int> >, int> mp;
    deque<pair<vector<int>, pair<int, int> > > q;
    q.push_back(m_p(p, m_p(s, 0)));
    mp[m_p(p, m_p(s, 0))] = 0;
    while (1)
    {
        pair<vector<int>, pair<int, int> > t = q.front();
        q.pop_front();
        bool z = true;
        if (t.se.fi != s)
            z = false;
        for (int i = 0; i < n; ++i)
        {
            if (t.fi[i] != i + 1)
            {
                z = false;
                break;
            }
        }
        if (z)
            return mp[t];

        pair<vector<int>, pair<int, int> > h;

        h = t;
        if (h.se.fi != n - 1)
        {
            ++h.se.fi;
            if (mp.find(h) == mp.end())
            {
                mp[h] = mp[t] + 1;
                q.push_back(h);
            }
        }

        h = t;
        if (h.se.fi != 0)
        {
            --h.se.fi;
            if (mp.find(h) == mp.end())
            {
                mp[h] = mp[t] + 1;
                q.push_back(h);
            }
        }

        h = t;
        swap(h.se.se, h.fi[h.se.fi]);
        if (mp.find(h) == mp.end())
        {
            mp[h] = mp[t];
            q.push_front(h);
        }
    }
}

int q[N];
long long minimum_walk(std::vector<int> p, int s)
{
    n = sz(p);
    ll ans = 0;
    for (int i = 0; i < n; ++i)
    {
        ans += abs(i - p[i]);
    }
    for (int i = 0; i < n; ++i)
    {
        q[min(i, p[i])]++;
        q[max(i, p[i])]--;
    }
    for (int i = 0; i < n; ++i)
    {
        q[i] += q[i - 1];
        if (!q[i])
        {
            bool zl = false;
            bool zr = false;
            for (int j = 0; j <= i; ++j)
            {
                if (j != p[j])
                {
                    zl = true;
                    break;
                }
            }
            for (int j = i + 1; j < n; ++j)
            {
                if (j != p[j])
                {
                    zr = true;
                    break;
                }
            }
            if (zr)
                ans += 2;
        }
    }
    //printf("%d\n", bfs(p, s));
    return ans;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:93:18: warning: variable 'zl' set but not used [-Wunused-but-set-variable]
   93 |             bool zl = false;
      |                  ^~

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