Submission #400799

#	Time	Username	Problem	Language	Result	Execution time	Memory
400799		idk321	Ancient Books (IOI17_books)	C++11	50 / 100	338 ms	106164 KiB

books

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

using namespace std;
typedef long long ll;

const int N = 1000000;

bool vis[N];
/*
bool tree[4 * N];

void push(int node)
{
    if (tree[node])
    {
        tree[node * 2] = true;
        tree[node * 2 +1] = true;
    }
}

void ins(int from, int to, int a, int b, int node)
{
    if (from <= a && b <= to)
    {
        tree[node] = true;
        return;
    }

    push(node);
    int mid = (a + b) / 2;
    if (from <= mid) ins(from, to, a, mid, node * 2);
    if (to > mid) ins(from, to, mid + 1, b, node * 2 + 1);
}

bool getIn(int i, int a, int b, int node)
{
    if (a == b) return tree[node];

    push(node);
    int mid = (a + b) / 2;
    if (i <= mid) return getIn(i, a, mid, node * 2);
    return getIn(i, mid + 1, b, node * 2 + 1);
} */

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

    ll res = 0;

    int n = p.size();

    vector<array<int, 2>> ivals;
    vector<array<int, 2>> landr(n);
    vector<int> comp(n);
    int compNum = 0;
    for (int i = 0; i < n; i++)
    {
        if (p[i] == i || vis[i]) continue;
        int cur = i;
        int l = cur;
        int r = cur;
        do
        {
            vis[cur] = true;
            l = min(l, cur);
            r = max(r, cur);
            res += abs(p[cur] - cur);
            //ins(min(cur, p[cur]), max(cur, p[cur]), 0, n - 1, 1);
            cur = p[cur];
        } while (cur != i);
        ivals.push_back({l, r});

        do
        {

            comp[cur] = compNum;

            //ins(min(cur, p[cur]), max(cur, p[cur]), 0, n - 1, 1);
            cur = p[cur];
        } while (cur != i);

        landr[compNum][0] = l;
        landr[compNum][1] = r;
        compNum++;
    }


    if (res == 0) return 0;
    sort(ivals.begin(), ivals.end());

    vector<array<int, 2>> together;

    int l = ivals[0][0];
    int r = ivals[0][1];
    for (int i = 1; i < ivals.size(); i++)
    {
        if (ivals[i][0] > r)
        {
            together.push_back({l, r});
            l = ivals[i][0];
            r = ivals[i][1];
        } else
        {
            r = max(ivals[i][1], r);
        }
    }
    together.push_back({l, r});




    for (int i = 1; i < together.size(); i++)
    {
        res += (together[i][0] - together[i - 1][1]) * 2;
    }

    if (s  < together[0][0])
    {
        res += (together[0][0] - s) * 2;
    }
    if (s > together[together.size() - 1][1])
    {
        res += (s - together[together.size() - 1][1]) * 2;
    }

    int in = -1;
    for (int i = 0; i < together.size(); i++)
    {
        if (s >= together[i][0] && s <= together[i][1])
        {
            in = i;
            break;
        }
    }


    if (in != -1)
    {
        vector<int> dist(n, -1);
        int cr = 0;
        int cl = 0;
        int cur = s;
        deque<array<int, 2>> que;
        que.push_back({comp[s], 0});
        while (!que.empty())
        {
            auto cur = que.front();
            que.pop_front();
            if (dist[cur[0]] != -1) continue;
            dist[cur[0]] = cur[1];


            for (int i = landr[cur[0]][0]; i <= landr[cur[0]][1]; i++)
            {
                que.push_front({comp[i], cur[1]});
            }
            if (landr[cur[0]][0] - 1 >= together[in][0])
            {
                que.push_back({comp[landr[cur[0]][0] - 1], cur[1] + 1});
            }
            if (landr[cur[0]][1] + 1 <= together[in][1])
            {
                que.push_back({comp[landr[cur[0]][1] + 1], cur[1] + 1});
            }
        }

        res += min(dist[comp[together[in][0]]], dist[comp[together[in][1]]]);
    }


    return res;
}

/*
4 0
0 2 3 1
*/

/*
5 2
0 4 3 2 1
*/

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:95:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |     for (int i = 1; i < ivals.size(); i++)
      |                     ~~^~~~~~~~~~~~~~
books.cpp:112:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |     for (int i = 1; i < together.size(); i++)
      |                     ~~^~~~~~~~~~~~~~~~~
books.cpp:127:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  127 |     for (int i = 0; i < together.size(); i++)
      |                     ~~^~~~~~~~~~~~~~~~~
books.cpp:140:13: warning: unused variable 'cr' [-Wunused-variable]
  140 |         int cr = 0;
      |             ^~
books.cpp:141:13: warning: unused variable 'cl' [-Wunused-variable]
  141 |         int cl = 0;
      |             ^~
books.cpp:142:13: warning: unused variable 'cur' [-Wunused-variable]
  142 |         int cur = s;
      |             ^~~

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