Submission #421493

#	Time	Username	Problem	Language	Result	Execution time	Memory
421493		MarcoMeijer	Ancient Books (IOI17_books)	C++14	50 / 100	211 ms	16116 KiB

books

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

// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

ll minimum_walk(vi p, int s) {
    int n = p.size();
    ll ans = 0;
    vi visited; visited.assign(n,0);

    /*if(s == 0) {
        ll rightMost = 0;

        RE(i,n) {
            if(visited[i]) continue;
            if(i == p[i]) continue;
            int u = p[i];
            ans += (ll)abs(i-p[i]);
            if(rightMost < i) ans += (i-rightMost)*2ll;
            while(u != i) {
                visited[u] = 1;
                rightMost = max<ll>(rightMost, u);
                ans += (ll)abs(u - p[u]);
                u = p[u];
            }
        }
    } else {*/
        int ls=s, rs=s;
        queue<int> q; q.push(s);

        while(ls != 0 || rs != n-1 || !q.empty()) {
            while(!q.empty()) {
                int i = q.front(); q.pop();
                if(visited[i]) continue;
                if(i == p[i]) continue;
                int u = p[i];
                ans += (ll)abs(i-p[i]);
                while(u != i) {
                    visited[u] = 1;
                    ans += (ll)abs(u - p[u]);

                    while(ls > u) q.push(--ls);
                    while(rs < u) q.push(++rs);

                    u = p[u];
                }
            }

            int leftSize = INF, rightSize = INF;
            REV(i,0   ,ls) if(p[i] != i) {
                leftSize  = ls - i;
                break;
            }
            REP(i,rs+1,n ) if(p[i] != i) {
                rightSize = i  - rs;
                break;
            }

            if(leftSize == INF && rightSize == INF) {
                break;
            }
            if(leftSize < rightSize) {
                RE(_,leftSize) q.push(--ls), ans += 2ll;
            } else {
                RE(_,rightSize) q.push(++rs), ans += 2ll;
            }
        }
    // }

	return ans;
}

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