oj.uz

Submission #800829

# Submission time Handle Problem Language Result Execution time Memory
800829 2023-08-01T23:36:01 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 10928 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 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() >= 2 * 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 / 2) {
        merge_blocks(i);
    }
    else if (i && blocks[i - 1].size() + blocks[i].size() <= BLOCK_SIZE / 2) {
        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;
        }
    }

    // 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 'void remove_from(int, int)':
elephants.cpp:127:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  127 |     else if (i != blocks.size() - 1 && blocks[i].size() + blocks[i + 1].size() <= BLOCK_SIZE / 2) {
      |              ~~^~~~~~~~~~~~~~~~~~~~
elephants.cpp: In function 'int update(int, int)':
elephants.cpp:154:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  154 |     for (int i = 0; i < blocks.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
elephants.cpp:164:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  164 |     for (int i = 0; i < blocks.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
elephants.cpp:165:50: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  165 |         if (blocks[i].positions.back() >= y || i == blocks.size() - 1) {
      |                                                ~~^~~~~~~~~~~~~~~~~~~~
elephants.cpp:174:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  174 |     for (int b = 0; b < blocks.size(); b++) {
      |                     ~~^~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

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

Subtask #2
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 304 KB Output is correct
4 Correct 1 ms 300 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 304 KB Output is correct
4 Correct 1 ms 300 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 769 ms 2232 KB Output is correct
8 Correct 1114 ms 2372 KB Output is correct
9 Correct 2498 ms 3792 KB Output is correct
10 Correct 2464 ms 3272 KB Output is correct
11 Correct 2386 ms 3236 KB Output is correct
12 Correct 3293 ms 3736 KB Output is correct
13 Correct 2633 ms 3028 KB Output is correct

Subtask #4
47.0 / 47.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 304 KB Output is correct
4 Correct 1 ms 300 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 769 ms 2232 KB Output is correct
8 Correct 1114 ms 2372 KB Output is correct
9 Correct 2498 ms 3792 KB Output is correct
10 Correct 2464 ms 3272 KB Output is correct
11 Correct 2386 ms 3236 KB Output is correct
12 Correct 3293 ms 3736 KB Output is correct
13 Correct 2633 ms 3028 KB Output is correct
14 Correct 1425 ms 3344 KB Output is correct
15 Correct 1924 ms 3448 KB Output is correct
16 Correct 4557 ms 4704 KB Output is correct
17 Correct 6575 ms 6076 KB Output is correct
18 Correct 6204 ms 5400 KB Output is correct
19 Correct 5817 ms 4944 KB Output is correct
20 Correct 6503 ms 6064 KB Output is correct
21 Correct 6443 ms 5484 KB Output is correct
22 Correct 5355 ms 4428 KB Output is correct

Subtask #5
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 304 KB Output is correct
4 Correct 1 ms 300 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 769 ms 2232 KB Output is correct
8 Correct 1114 ms 2372 KB Output is correct
9 Correct 2498 ms 3792 KB Output is correct
10 Correct 2464 ms 3272 KB Output is correct
11 Correct 2386 ms 3236 KB Output is correct
12 Correct 3293 ms 3736 KB Output is correct
13 Correct 2633 ms 3028 KB Output is correct
14 Correct 1425 ms 3344 KB Output is correct
15 Correct 1924 ms 3448 KB Output is correct
16 Correct 4557 ms 4704 KB Output is correct
17 Correct 6575 ms 6076 KB Output is correct
18 Correct 6204 ms 5400 KB Output is correct
19 Correct 5817 ms 4944 KB Output is correct
20 Correct 6503 ms 6064 KB Output is correct
21 Correct 6443 ms 5484 KB Output is correct
22 Correct 5355 ms 4428 KB Output is correct
23 Execution timed out 9100 ms 10928 KB Time limit exceeded
24 Halted 0 ms 0 KB -