Submission #109394

#	Time	Username	Problem	Language	Result	Execution time	Memory
109394		JustasZ	Ancient Books (IOI17_books)	C++14	22 / 100	1349 ms	1049600 KiB

books

#include "books.h"
#include <bits/stdc++.h>
#define pb push_back
#define x first
#define y second
#define all(a) a.begin(), a.end()
#define sz(a) (int)a.size()
#define rd() abs((int)rng())
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
const int maxn = 1e6 + 100;
const int mod = 1e9 + 7;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
int n, s, val[maxn], nxt, L[maxn], R[maxn];
vector<vector<int> > edge;
vector<int>p;
vector<pair<int, pii> > edges;
ll ans;
int par[maxn];
int root(int v)
{
    return v == par[v] ? v : par[v] = root(par[v]);
}
bool unite(int a, int b)
{
    a = root(a), b = root(b);
    if(a == b)
        return false;
    par[b] = a;
    return true;
}
void clr()
{
    for(int i = 0; i < maxn; i++)
    {
        L[i] = mod;
        R[i] = -mod;
    }
    ans = 0;
    nxt = 0;
    edges.clear();
    memset(val, 0, sizeof val);
}
ll minimum_walk(vector<int>perm, int S)
{
    clr();
    s = S;
    p = perm;
    n = sz(p);
    set<int>one;
    for(int i = 0; i < n; i++)
    {
        if(!val[i])
        {
            int col = ++nxt, cur = i, cnt = 0, chk = 0;
            while(!val[cur])
            {
                //cout << "-- " << cur << " " << col << endl;
                L[col] = min(L[col], cur);
                R[col] = max(R[col], cur);
                if(cur == s)
                    chk = 1;
                cnt++;
                val[cur] = col;
                ans += abs(p[cur] - cur);
                cur = p[cur];
            }
            if(cnt == 1 && !chk)
                one.insert(col);
        }
    }
    vector<int>belong[nxt + 1];
    for(int i = 0; i < n; i++)
        belong[val[i]].pb(i);
    edge = vector<vector<int> > (n, vector<int>(n, mod));
    for(int i = 0; i < n; i++)
    {
        for(int j = i + 1; j < n; j++)
        {
            if(val[i] != val[j])
                edge[val[i]][val[j]] = min(edge[val[i]][val[j]], j - i);
        }
    }
    for(int i = 1; i <= nxt; i++)
    {
        //cout << i << " " << L[i] << " " << R[i] << endl;
        for(int j = 1; j <= nxt; j++)
        {
            if(i == j)
                continue;
            for(int a : belong[i])
            {
                for(int b : belong[j])
                {
                    if((a < b && p[a] > b) || (a > b && p[a] < b))
                        edge[i][j] = edge[j][i] = 0;
                }
                //if((a < L[j] && p[a] > R[j]) || (a > R[j] && p[a] < L[j]))
                    //edge[i][j] = edge[j][i] = 0;

            }
        }
    }
    for(int i = 1; i <= nxt; i++)
        par[i] = i;
    for(int i = 1; i <= nxt; i++)
        for(int j = i + 1; j <= nxt; j++)
            edges.pb({edge[i][j], {i, j}});
    sort(all(edges));
    for(auto aa : edges)
    {
        if(one.count(aa.y.x) || one.count(aa.y.y))
            continue;
        if(unite(aa.y.x, aa.y.y))
            ans += aa.x * 2;
    }
    return ans;
}
/*int main()
{
    ios_base::sync_with_stdio(false), cin.tie(0);
    vector<int>perm;
    for(int i = 0; i < 4; i++)
        perm.pb(i);
    do
    {
        for(int i = 0; i < 4; i++)
        {
            clr();
            cout << "permutaiton ";
            for(int a : perm)
                cout << a << " ";
            cout << endl;
            cout << "start: " << i << " " << minimum_walk(perm, i) << endl;
        }
    } while(next_permutation(all(perm)));
    ifstream fin("in.txt");
    int n, s;
    fin >> n >> s;
    perm.resize(n);
    for(int i = 0; i < n; i++)
        fin >> perm[i];
    cout << minimum_walk(perm, s) << endl;
    cout << minimum_walk({3, 2, 1, 0}, 0);
    return 0;
}*/

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