oj.uz

Submission #800842

# Submission time Handle Problem Language Result Execution time Memory
800842 2023-08-02T00:08:44 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 5848 KB 
#include "elephants.h"
#include <bits/stdc++.h>
#define f first
#define s second
#define mp make_pair

using namespace std;

typedef pair<int, int> pi;

struct Block {
  vector<int> positions;

  // photos[i]: Photos required and maximum position if the first elephant to be photographed is i
  vector<pi> photos;

    int size(void) {
        return positions.size();
    }
};

int N, L;
int upd = 0;
int ttl_blocks;
int BLOCK_SIZE;
vector<int> loc;
vector<Block> blocks;

bool onlyfirst(const pi& a, const pi& b)
{
    return a.f < b.f;
}

void create_photos(Block& b)
{
    int sz = b.positions.size();
    b.photos.resize(sz);

    for (int i = sz - 1; i >= 0; i--) {
        int e = upper_bound(b.positions.begin(), b.positions.end(), b.positions[i] + L) - b.positions.begin();

        if (e == sz) {
            b.photos[i] = mp(b.positions[i] + L + 1, 1);
        }
        else {
            b.photos[i] = b.photos[e];
            b.photos[i].s++;
        }
    }
}

// Merge blocks b and b + 1
void merge_blocks(int b)
{
    for (int i = 0; i < blocks[b + 1].size(); i++)
        blocks[b].positions.push_back(blocks[b + 1].positions[i]);

    blocks.erase(blocks.begin() + b + 1);

    create_photos(blocks[b]);
}

// Split block b
void split_block(int b)
{
    int mid = blocks[b].size() / 2;

    Block b1, b2;
    for (int i = 0; i < mid; i++)
        b1.positions.push_back(blocks[b].positions[i]);
    for (int i = mid; i < blocks[b].size(); i++)
        b2.positions.push_back(blocks[b].positions[i]);

    blocks.erase(blocks.begin() + b);
    blocks.insert(blocks.begin() + b, b2);
    blocks.insert(blocks.begin() + b, b1);

    create_photos(blocks[b]);
    create_photos(blocks[b + 1]);
}

void init(int n, int l, int X[])
{
    N = n;
    L = l;
    BLOCK_SIZE = sqrt(N);

    loc.resize(N);

    blocks.resize(1);
    for (int i = 0; i < N; i++) {

        blocks[i / BLOCK_SIZE].positions.push_back(X[i]);
        loc[i] = X[i];

        if (i + 1 == N || (i + 1) % BLOCK_SIZE == 0) {
            create_photos(blocks[i / BLOCK_SIZE]);
            if (i + 1 != N) {
                blocks.push_back({vector<int>(), vector<pi>()});
            }
        }
    }
}

void insert_at(int i, int v)
{
    int pos = lower_bound(blocks[i].positions.begin(), blocks[i].positions.end(), v) - blocks[i].positions.begin();

    blocks[i].positions.insert(blocks[i].positions.begin() + pos, v);

    // if (blocks[i].size() >= BLOCK_SIZE) {
    //     split_block(i);
    // }
    // else {
        create_photos(blocks[i]);
    // }
}

void remove_from(int i, int v)
{
    int pos = lower_bound(blocks[i].positions.begin(), blocks[i].positions.end(), v) - blocks[i].positions.begin();

    blocks[i].positions.erase(blocks[i].positions.begin() + pos);

    if (blocks[i].size() == 0) {
        blocks.erase(blocks.begin() + i);
    }
    // else if (i != blocks.size() - 1 && blocks[i].size() + blocks[i + 1].size() <= BLOCK_SIZE) {
    //     merge_blocks(i);
    // }
    // else if (i && blocks[i - 1].size() + blocks[i].size() <= BLOCK_SIZE) {
    //     merge_blocks(i - 1);
    // }
    else {
        create_photos(blocks[i]);
    }
}

pi calculate_block(int i, int pos)
{
    Block b = blocks[i];
    if (b.positions.back() < pos)
        return mp(pos, 0);

    int at = lower_bound(b.positions.begin(), b.positions.end(), pos) - b.positions.begin();

    return b.photos[at];
}

int update(int pos, int y)
{
    // Find the block in which i belongs to and in which block it will go
    // First remove the element
    int prev = loc[pos];
    for (int i = 0; i < blocks.size(); i++) {
        if (blocks[i].positions.back() >= prev) {
            // Insert at previous block
            remove_from(i, prev);
            break;
        }
    }

    loc[pos] = y;
    // Then insert
    for (int i = 0; i < blocks.size(); i++) {
        if (blocks[i].positions.back() >= y || i == blocks.size() - 1) {
            // Insert at previous block
            insert_at(i, y);
            break;
        }
    }

    // After some updates, rebuild
    upd++;
    if (upd == BLOCK_SIZE + 1) {
        blocks.clear();
        vector<int> p = loc;
        sort(p.begin(), p.end());
        blocks.resize(1);
        for (int i = 0; i < N; i++) {

            blocks[i / BLOCK_SIZE].positions.push_back(p[i]);

            if (i + 1 == N || (i + 1) % BLOCK_SIZE == 0) {
                create_photos(blocks[i / BLOCK_SIZE]);
                if (i + 1 != N) {
                    blocks.push_back({vector<int>(), vector<pi>()});
                }
            }
        }
        upd = 0;
    }

    // Recalculate the photos
    pi ans = mp(0, 0);
    for (int b = 0; b < blocks.size(); b++) {
        pi nxt = calculate_block(b, ans.f);

        ans.f = nxt.f;
        ans.s += nxt.s;
    }

    return ans.s;
}

Compilation message

elephants.cpp: In function 'int update(int, int)':
elephants.cpp:155:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  155 |     for (int i = 0; i < blocks.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
elephants.cpp:165:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  165 |     for (int i = 0; i < blocks.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
elephants.cpp:166:50: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  166 |         if (blocks[i].positions.back() >= y || i == blocks.size() - 1) {
      |                                                ~~^~~~~~~~~~~~~~~~~~~~
elephants.cpp:196:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  196 |     for (int b = 0; b < blocks.size(); b++) {
      |                     ~~^~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct

Subtask #2
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 304 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 304 KB Output is correct
7 Correct 976 ms 1268 KB Output is correct
8 Correct 1554 ms 1420 KB Output is correct
9 Correct 2993 ms 2316 KB Output is correct
10 Correct 3329 ms 2192 KB Output is correct
11 Correct 3162 ms 2288 KB Output is correct
12 Correct 3732 ms 2476 KB Output is correct
13 Correct 3393 ms 2228 KB Output is correct

Subtask #4
47.0 / 47.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 304 KB Output is correct
7 Correct 976 ms 1268 KB Output is correct
8 Correct 1554 ms 1420 KB Output is correct
9 Correct 2993 ms 2316 KB Output is correct
10 Correct 3329 ms 2192 KB Output is correct
11 Correct 3162 ms 2288 KB Output is correct
12 Correct 3732 ms 2476 KB Output is correct
13 Correct 3393 ms 2228 KB Output is correct
14 Correct 2025 ms 1760 KB Output is correct
15 Correct 2383 ms 1768 KB Output is correct
16 Correct 5593 ms 2608 KB Output is correct
17 Correct 7701 ms 3452 KB Output is correct
18 Correct 7735 ms 3556 KB Output is correct
19 Correct 6993 ms 3236 KB Output is correct
20 Correct 7791 ms 3532 KB Output is correct
21 Correct 7639 ms 3584 KB Output is correct
22 Correct 6932 ms 3236 KB Output is correct

Subtask #5
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 304 KB Output is correct
7 Correct 976 ms 1268 KB Output is correct
8 Correct 1554 ms 1420 KB Output is correct
9 Correct 2993 ms 2316 KB Output is correct
10 Correct 3329 ms 2192 KB Output is correct
11 Correct 3162 ms 2288 KB Output is correct
12 Correct 3732 ms 2476 KB Output is correct
13 Correct 3393 ms 2228 KB Output is correct
14 Correct 2025 ms 1760 KB Output is correct
15 Correct 2383 ms 1768 KB Output is correct
16 Correct 5593 ms 2608 KB Output is correct
17 Correct 7701 ms 3452 KB Output is correct
18 Correct 7735 ms 3556 KB Output is correct
19 Correct 6993 ms 3236 KB Output is correct
20 Correct 7791 ms 3532 KB Output is correct
21 Correct 7639 ms 3584 KB Output is correct
22 Correct 6932 ms 3236 KB Output is correct
23 Execution timed out 9068 ms 5848 KB Time limit exceeded
24 Halted 0 ms 0 KB -