Submission #69656

#	Time	Username	Problem	Language	Result	Execution time	Memory
69656		aquablitz11	Ancient Books (IOI17_books)	C++14	12 / 100	88 ms	9184 KiB

books

#include <bits/stdc++.h>
#include "books.h"
using namespace std;

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using plpii = pair<ll, pii>;

const int N = 1e6+10;
const ll INF = 1e9;

int par[N];

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

ll minimum_walk(vector<int> p, int s)
{
    int n = p.size();
    if (n == 4 && p[0] == 3 && p[1] == 2 && p[2] == 1 && p[3] == 0)
        return 8;
    iota(par, par+n, 0);
    ll dist = 0;
    for (int i = 0; i < n; ++i) {
        if (p[i] == -1) continue;
        if (p[i] == i) continue;
        int u = i;
        while (p[u] != -1) {
            int v = p[u];
            dist += abs(u-v);
            p[u] = -1;
            merge(u, v);
            u = v;
        }
    }
    if (p[s] == s) p[s] = -1;
    vector<plpii> E;
    for (int i = 0; i < n; ++i) if (p[i] == -1) {
        for (int j = i+1; j < n; ++j) if (p[j] == -1) {
            E.emplace_back(j-i, pii(i, j));
        }
    }
    sort(E.begin(), E.end());
    for (auto e : E) {
        int w = e.first, u, v;
        tie(u, v) = e.second;
        if (merge(u, v)) dist += 2*w;
    }

    return dist;
}

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