Submission #1061496

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061496		Zicrus	Ancient Books (IOI17_books)	C++17	50 / 100	107 ms	26792 KiB

books

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

typedef long long ll;

ll minimum_walk(vector<int> p, int s) {
    ll n = p.size();
	ll res = 0;
    for (int i = 0; i < n; i++) res += abs(p[i] - i);

    vector<bool> vst(n);
    vector<vector<ll>> cyc;
    vector<ll> mxCyc;
    for (int i = 0; i < n; i++) {
        if (vst[i] || p[i] == i) continue;
        cyc.push_back(vector<ll>());
        mxCyc.push_back(i);
 
        ll cur = i;
        do {
            cyc.back().push_back(cur);
            mxCyc.back() = max(mxCyc.back(), cur);
            cur = p[cur];
            vst[cur] = true;
        } while (cur != i);
    }
    ll m = cyc.size();

    ll mx = 0;
    bool done = false;
    for (int i = 1; i < m; i++) {
        mx = max(mx, mxCyc[i-1]);
        if (s <= cyc[i][0] && s >= mx) done = true;
        res += 2*max(0ll, cyc[i][0] - mx);
    }

    if (m == 0 || done) return res;
    int mnDist = n;
    for (int i = 0; i < n; i++) {
        if (p[i] == i) continue;
        mnDist = min(mnDist, abs(s - i));
    }
    return res + 2*mnDist;
}

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