Submission #1030369

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030369		shiomusubi496	Ancient Books (IOI17_books)	C++17	50 / 100	91 ms	15184 KiB

books

#include "books.h"

#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rep2(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define rrep(i, n) for (int i = (int)(n) - 1; i >= 0; --i)
#define rrep2(i, a, b) for (int i = (int)(b) - 1; i >= (int)(a); --i)

#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)

using namespace std;

using ll = long long;

template<class T, class U> bool chmin(T& a, const U& b) { return a > b ? a = b, true : false; }
template<class T, class U> bool chmax(T& a, const U& b) { return a < b ? a = b, true : false; }

long long minimum_walk(std::vector<int> p, int s) {
    int n = p.size();
    if (is_sorted(all(p))) return 0;
    ll ans = 0;
    {
        while (p.back() == n - 1) {
            if (s == n - 1) {
                --s;
                ans += 2;
            }
            p.pop_back();
            --n;
        }
        reverse(all(p));
        rep (i, n) p[i] = n - 1 - p[i];
        s = n - 1 - s;
        while (p.back() == n - 1) {
            if (s == n - 1) {
                --s;
                ans += 2;
            }
            p.pop_back();
            --n;
        }
        reverse(all(p));
        rep (i, n) p[i] = n - 1 - p[i];
        s = n - 1 - s;
    }
    ll cur = 0;
    vector<bool> seen(n);
    rep (i, n) {
        if (seen[i]) continue;
        int j = i;
        ll mx = 0;
        do {
            seen[j] = true;
            chmax(mx, j);
            j = p[j];
        } while (j != i);
        if (cur < i) ans += 2;
        chmax(cur, mx);
    }
    rep (i, n) ans += abs(p[i] - i);
    return ans;
}

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