Submission #1082526

#	Time	Username	Problem	Language	Result	Execution time	Memory
1082526		Boas	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	9 ms	600 KiB

longesttrip

#include "longesttrip.h"

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;

template <typename T1, typename T2>
using indexed_map = tree<T1, T2, less<T1>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T>
using indexed_set = indexed_map<T, null_type>;

#define loop(x, i) for (int i = 0; i < (x); i++)
#define loop1(x, i) for (int i = 1; i <= (x); i++)
#define rev(x, i) for (int i = (int)(x) - 1; i >= 0; i--)
#define itloop(x) for (auto it = begin(x); x != end(x); it++)
#define itrev(x) for (auto it = rbegin(x); x != rend(x); it++)
#define INF32 ((int32_t)(2e9 + 1))
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define removeIn(x, l) l.erase(find(ALL(l), x))
#define pb push_back
#define sz(x) (int)(x).size()
#define F first
#define S second
#define var const auto &
#define foreach(l) for (var e : l)

typedef int8_t i8;
typedef int16_t i16;
typedef int32_t i32;
typedef int64_t i64;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<i32> vi32;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vi32> vvi32;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<vii> vvii;
typedef vector<viii> vviii;
typedef set<int> si;
typedef set<ii> sii;
typedef set<iii> siii;
typedef vector<si> vsi;
typedef vector<sii> vsii;
typedef vector<vsi> vvsi;
typedef vector<string> vstr;
typedef vector<vector<string>> vvstr;
typedef vector<bool> vb;
typedef vector<vb> vvb;

vi longest_trip(int N, int D)
{
    if (D >= 2)
    {
        vi res(N);
        iota(ALL(res), 0);
        if (D == 3)
        {
            return res;
        }
        si resterend;
        loop1(N - 1, i) resterend.insert(res[i]);
        loop1(N - 1, i)
        {
            auto it = resterend.begin();
            if (are_connected({res[i - 1]}, {*it}))
            {
                res[i] = *it;
                resterend.erase(it);
            }
            else
            {
                if (resterend.size() == 1)
                {
                    res.insert(res.begin(), *it);
                    res.pop_back();
                    return res;
                }
                res[i] = *next(it);
                resterend.erase(next(it));
            }
        }
        return res;
    }
    else
    {
        map<ii, bool> con;
        auto getCon = [&](int a, int b) -> bool
        {
            if (a > b)
                swap(a, b);
            assert(a != b);
            if (con.count({a, b}))
                return con[{a, b}];
            return con[{a, b}] = are_connected({a}, {b});
        };
        deque<int> path1, path2;
        path1.pb(0);
        for (int i = 1; i < N; i++)
        {
            if (getCon(i, path1.back()))
            {
                path1.pb(i);
            }
            else if (!path2.empty() && getCon(i, path2[0]))
            {
                path2.push_front(i);
            }
            else
            {
                for (int v : path2)
                    path1.pb(v);
                path2.clear();
                path2.pb(i);
            }
        }
        vi res;
        if (sz(path1) < sz(path2))
            swap(path1, path2);

        vi uq(ALL(path1)), vq(ALL(path2));
        if (sz(path1) == N)
            return vi(ALL(path1));
        assert(!uq.empty());
        assert(!vq.empty());
        if (are_connected(uq, vq))
        {
            if (!getCon(path1[0], path1.back()))
            {
                if (getCon(path1[0], path2[0]))
                {
                    rev(sz(path1), ix) res.pb(path1[ix]);
                    for (int i : path2)
                        res.pb(i);
                    return res;
                }
                else
                {
                    for (int i : path1)
                        res.pb(i);
                    for (int i : path2)
                        res.pb(i);
                    return res;
                }
            }
            int lo = 0, hi = sz(uq) - 1;
            while (hi > lo)
            {
                int mid = (lo + hi) / 2;
                vi uq2(begin(uq), begin(uq) + mid + 1);
                if (are_connected(uq2, vq))
                {
                    hi = mid;
                }
                else
                    lo = mid + 1;
            }
            int tar1 = path1[lo];
            lo = 0, hi = sz(vq) - 1;
            while (hi > lo)
            {
                int mid = (lo + hi) / 2;
                vi vq2(begin(vq), begin(vq) + mid + 1);
                if (are_connected(uq, vq2))
                {
                    hi = mid;
                }
                else
                    lo = mid + 1;
            }
            int tar2 = path2[lo], s1 = -1, s2 = -1;
            loop(sz(path1), ix)
            {
                if (path1[ix] == tar1)
                {
                    s1 = ix;
                }
            }
            loop(sz(path2), ix)
            {
                if (path2[ix] == tar2)
                {
                    s2 = ix;
                }
            }
            assert(s1 != -1 && s2 != -1);
            for (int i = s1 + 1; i < sz(path1); i++)
            {
                res.pb(path1[i]);
            }
            for (int i = 0; i <= s1; i++)
            {
                res.pb(path1[i]);
            }
            for (int i = s2; i < sz(path2); i++)
            {
                res.pb(path2[i]);
            }
            for (int i = 0; i < s2; i++)
            {
                res.pb(path2[i]);
            }
        }
        else
        {
            if (sz(path1) > sz(path2))
            {
                for (int v : path1)
                    res.pb(v);
            }
            else
            {
                for (int v : path2)
                    res.pb(v);
            }
            return res;
        }
        assert(sz(res) == N);
        // loop(sz(res) - 1, i) assert(con[res[i]][res[i + 1]]);
        return res;
    }
    throw;
    return {};
}

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 25
• Subtask 4: 0 / 60