Submission #1209120

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209120		jer033	Ancient Books (IOI17_books)	C++20	50 / 100	97 ms	10428 KiB

books

#include "books.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;

long long minimum_walk(std::vector<int> p, int s) {
    int n = p.size();
	ll base_cost = 0;
    for (int i=0; i<n; i++)
        base_cost += abs(p[i]-i);
    vector<pii> cycles;
    vector<bool> used(n, 0);
    for (int i=0; i<n; i++)
        if (used[i]==0)
        {
            used[i]=1;
            int mini = i;
            int maxi = i;
            int curr = p[i];
            while (curr!=i)
            {
                used[curr] = 1;
                maxi = max(curr, maxi);
                curr = p[curr];
            }
            if (mini!=maxi)
                cycles.push_back({mini, maxi});
        }
    int k = cycles.size();
    ll penalty = 0;
    int curr_max = -1;
    for (int i=0; i<k; i++)
    {
        if (i==0)
            penalty = cycles[0].first;
        else if (cycles[i].first > curr_max)
            penalty += cycles[i].first - curr_max;
        curr_max = max(curr_max, cycles[i].second);
    }
    return base_cost + 2ll*penalty;
}

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