Submission #916271

#	Time	Username	Problem	Language	Result	Execution time	Memory
916271		boris_mihov	Minerals (JOI19_minerals)	C++17	40 / 100	18 ms	2272 KiB

minerals

#include "minerals.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <random>
#include <vector>
#include <queue>

typedef long long llong;
const int MAXN = 86000 + 10;
const int INF  = 1e9;

int n;
struct Node
{
    int idx;
    int level;
    int l, r;
    int qL, qR;
};

int perm[MAXN];
bool isIn[MAXN];
std::vector <int> unique;
std::vector <int> second;
std::vector <int> secondCopy;
std::deque <Node> waitlist;
std::mt19937 rng(69420);

int countDiff;
int query(int idx)
{
    isIn[idx] ^= 1;
    return countDiff = Query(perm[idx]);
}

void answer(int a, int b)
{
    Answer(perm[a], perm[b]);
}

void Solve(int N) 
{
    n = N;
    std::iota(perm + 1, perm + 1 + 2 * n, 1);
    // std::shuffle(perm + 1, perm + 1 + 2 * n, rng);

    unique.push_back(0);
    unique.push_back(1);
    second.push_back(0);
    query(1);
    int last = 1;

    for (int i = 2 ; i <= 2 * n ; ++i)
    {
        if (query(i) > last)
        {
            last++;
            unique.push_back(i);
        } else
        {
            second.push_back(i);
        }
    }

    waitlist.push_front({1, 1, 1, n, 1, n});
    assert(unique.size() == n + 1);
    assert(second.size() == n + 1);
    secondCopy.resize(n + 1);

    int ptr = n;
    int lastLevel = 1;
    int reversed = 1;

    while (waitlist.size())
    {
        auto [idx, level, l, r, qL, qR] = waitlist.front();
        if (level != reversed)
        {
            reversed = level;
            std::reverse(waitlist.begin(), waitlist.end());
            continue;
        }

        waitlist.pop_front();

        assert(r - l + 1 == qR - qL + 1);
        if (l == r)
        {
            assert(qL == qR);
            answer(unique[l], second[qL]);
            continue;
        }

        int mid = (l + r) / 2;
        if (level != lastLevel)
        {
            if (level & 1)
            {
                while (ptr < mid)
                {
                    ptr++;
                    query(unique[ptr]);
                }
            } else
            {
                while (ptr > mid)
                {
                    query(unique[ptr]);
                    ptr--;
                }
            }

            lastLevel = level;
        }

        if (level & 1)
        {
            while (ptr > mid)
            {
                query(unique[ptr]);
                ptr--;
            }
        } else
        {
            while (ptr < mid)
            {
                ptr++;
                query(unique[ptr]);
            }
        }

        int myL = qL;
        int myR = qR;
        for (int idx = qL ; idx <= qR ; ++idx)
        {
            int last = countDiff;
            int curr = query(second[idx]);
            if (curr == last)
            {
                secondCopy[myL++] = second[idx];
            } else
            {
                secondCopy[myR--] = second[idx];
            }
        }

        for (int idx = qL ; idx <= qR ; ++idx)
        {
            second[idx] = secondCopy[idx];
        }
        
        assert(qL < myL);
        assert(myR < qR);
        if (level & 1)
        {
            waitlist.push_back({2 * idx + 1, level + 1, mid + 1, r, myR + 1, qR});
            waitlist.push_back({2 * idx, level + 1, l, mid, qL, myL - 1});
        } else
        {
            waitlist.push_back({2 * idx, level + 1, l, mid, qL, myL - 1});
            waitlist.push_back({2 * idx + 1, level + 1, mid + 1, r, myR + 1, qR});
        }
    }
}

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from minerals.cpp:5:
minerals.cpp: In function 'void Solve(int)':
minerals.cpp:68:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   68 |     assert(unique.size() == n + 1);
      |            ~~~~~~~~~~~~~~^~~~~~~~
minerals.cpp:69:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   69 |     assert(second.size() == n + 1);
      |            ~~~~~~~~~~~~~~^~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 25 / 25
• Subtask 3: 9 / 9
• Subtask 4: 0 / 30
• Subtask 5: 0 / 5
• Subtask 6: 0 / 5
• Subtask 7: 0 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 10