Submission #1011932

#	Time	Username	Problem	Language	Result	Execution time	Memory
1011932		c2zi6	Ancient Books (IOI17_books)	C++14	100 / 100	105 ms	20140 KiB

books

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define replr(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define reprl(i, a, b) for (int i = int(a); i >= int(b); --i)
#define rep(i, n) for (int i = 0; i < int(n); ++i)
#define mkp(a, b) make_pair(a, b)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VPI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
typedef vector<VPI> VVPI;
typedef pair<ll, ll> PLL;
typedef vector<ll> VL;
typedef vector<PLL> VPL;
typedef vector<VL> VVL;
typedef vector<VVL> VVVL;
typedef vector<VPL> VVPL;
template<class T> T setmax(T& a, T b) {if (a < b) return a = b; return a;}
template<class T> T setmin(T& a, T b) {if (a < b) return a; return a = b;}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<class T>
using indset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#include "books.h"

VI L, R, C;

void extend(int& l, int& r) {
    int ll = min(L[C[l]], L[C[r]]);
    int rr = max(R[C[l]], R[C[r]]);
    while (ll < l || r < rr) {
        if (ll < l) {
            l--;
            setmin(ll, L[C[l]]);
            setmax(rr, R[C[l]]);
        } else if (r < rr) {
            r++;
            setmin(ll, L[C[r]]);
            setmax(rr, R[C[r]]);
        }
    }
}

ll minimum_walk(VI p, int s) {
    int n = p.size();
    C = VI(n, -1);
    int c = 0;
    ll ans = 0;
    int entl = +2e9, entr = -2e9;
    rep(i, n) if (C[i] == -1) {
        int u = i;
        int l = +2e9, r = -2e9;
        do {
            C[u] = c;
            setmin(l, u);
            setmax(r, u);
            ans += abs(p[u]-u);
            u = p[u];
        } while (u != i);
        L.pb(l);
        R.pb(r);
        if (i != p[i]) {
            setmin(entl, l);
            setmax(entr, r);
        }
        c++;
    }

    int l = s;
    int r = s;
    while (true) {
        extend(l, r);
        int al = l;
        int ar = r;
        int ac = 0;
        while (ar < entr && al == l) {
            extend(al, ++ar);
            ac += 2;
        }
        int bl = l;
        int br = r;
        int bc = 0;
        while (bl > entl && br == r) {
            extend(--bl, br);
            bc += 2;
        }
        if (al == l) {
            ans += ac + bc;
            break;
        }
        ans += min(ac, bc);
        l = al;
        r = br;
    }
    return ans;
}

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