Submission #836917

#	Time	Username	Problem	Language	Result	Execution time	Memory
836917		borisAngelov	Examination (JOI19_examination)	C++17	100 / 100	540 ms	35852 KiB

examination

#include <bits/stdc++.h>

using namespace std;

const int maxn = 600005;
const int max_number = 600000;

int n, q;

struct element
{
    int x;
    int y;
    int z;
    bool is_query;
    int query_idx;

    element()
    {

    }

    element(int _x, int _y, int _z, bool _is_query, int _query_idx)
    {
        x = _x;
        y = _y;
        z = _z;
        is_query = _is_query;
        query_idx = _query_idx;
    }
};

element a[maxn];

void compress()
{
    vector<int> to_sort;
    unordered_map<int, int> compressed;
    int curr_value = 0;

    for (int i = 1; i <= n + q; ++i)
    {
        to_sort.push_back(a[i].x);
        to_sort.push_back(a[i].y);
        to_sort.push_back(a[i].z);
    }

    sort(to_sort.begin(), to_sort.end());

    for (int i = 0; i < to_sort.size(); ++i)
    {
        if (i == 0 || to_sort[i] != to_sort[i - 1])
        {
            compressed[to_sort[i]] = ++curr_value;
        }
    }

    for (int i = 1; i <= n + q; ++i)
    {
        a[i].x = compressed[a[i].x];
        a[i].y = compressed[a[i].y];
        a[i].z = compressed[a[i].z];
    }
}

int answers[maxn];

struct fenwick_tree
{
    int tree[maxn];

    void update(int pos, int delta)
    {
        for (int i = pos; i <= max_number; i += (i & (-i)))
        {
            tree[i] += delta;
        }
    }

    int query(int pos)
    {
        int result = 0;

        for (int i = pos; i >= 1; i -= (i & (-i)))
        {
            result += tree[i];
        }

        return result;
    }
};

fenwick_tree bit;

void divide_and_conquer(int l, int r)
{
    if (l == r)
    {
        return;
    }

    int mid = (l + r) / 2;

    vector<element> active;

    for (int i = l; i <= mid; ++i)
    {
        if (a[i].is_query == false)
        {
            active.push_back(element(0, a[i].y, a[i].z, false, 0));
        }
    }

    for (int i = mid + 1; i <= r; ++i)
    {
        if (a[i].is_query == true)
        {
            active.push_back(element(0, a[i].y, a[i].z, true, a[i].query_idx));
        }
    }

    sort(active.begin(), active.end(), [&](element fr, element sc)
    {
        return make_pair(fr.y, -fr.is_query) > make_pair(sc.y, -sc.is_query);
    });

    vector<int> pos_to_clear;

    for (int i = 0; i < active.size(); ++i)
    {
        if (active[i].is_query == false)
        {
            bit.update(active[i].z, +1);
            pos_to_clear.push_back(active[i].z);
        }
        else
        {
            answers[active[i].query_idx] += (bit.query(max_number) - bit.query(active[i].z - 1));
        }
    }

    for (int i = 0; i < pos_to_clear.size(); ++i)
    {
        bit.update(pos_to_clear[i], -1);
    }

    divide_and_conquer(l, mid);
    divide_and_conquer(mid + 1, r);
}

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n >> q;

    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i].x >> a[i].y;
        a[i].z = a[i].x + a[i].y;
    }

    for (int i = 1; i <= q; ++i)
    {
        cin >> a[i + n].x >> a[i + n].y >> a[i + n].z;
        a[i + n].is_query = true;
        a[i + n].query_idx = i;
    }

    compress();

    sort(a + 1, a + n + q + 1, [&](element fr, element sc)
    {
        return make_pair(fr.x, -fr.is_query) > make_pair(sc.x, -sc.is_query);
    });

    divide_and_conquer(1, n + q);

    for (int i = 1; i <= q; ++i)
    {
        cout << answers[i] << "\n";
    }

    return 0;
}

/*
5 4
35 100
70 70
45 15
80 40
20 95
20 50 0
10 10 0
60 60 0
0 100 0

5 4
35 100
70 70
45 15
80 40
20 95
20 50 120
10 10 100
60 60 80
0 100 100
*/

Compilation message (stderr)

examination.cpp: In function 'void compress()':
examination.cpp:50:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |     for (int i = 0; i < to_sort.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~~~
examination.cpp: In function 'void divide_and_conquer(int, int)':
examination.cpp:129:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<element>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |     for (int i = 0; i < active.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~~
examination.cpp:142:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  142 |     for (int i = 0; i < pos_to_clear.size(); ++i)
      |                     ~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 2 / 2
• Subtask 2: 20 / 20
• Subtask 3: 21 / 21
• Subtask 4: 57 / 57