oj.uz

Submission #800833

# Submission time Handle Problem Language Result Execution time Memory
800833 2023-08-01T23:43:20 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 5996 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() >= 3 * BLOCK_SIZE / 2) {
        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() <= 3 * BLOCK_SIZE / 4) {
        merge_blocks(i);
    }
    else if (i && blocks[i - 1].size() + blocks[i].size() <= 3 * BLOCK_SIZE / 4) {
        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() <= 3 * BLOCK_SIZE / 4) {
      |              ~~^~~~~~~~~~~~~~~~~~~~
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 0 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 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 432 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 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 432 KB Output is correct
7 Correct 713 ms 1200 KB Output is correct
8 Correct 1087 ms 1400 KB Output is correct
9 Correct 2547 ms 2372 KB Output is correct
10 Correct 2796 ms 1992 KB Output is correct
11 Correct 2600 ms 1996 KB Output is correct
12 Correct 3146 ms 2460 KB Output is correct
13 Correct 2971 ms 1996 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 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 432 KB Output is correct
7 Correct 713 ms 1200 KB Output is correct
8 Correct 1087 ms 1400 KB Output is correct
9 Correct 2547 ms 2372 KB Output is correct
10 Correct 2796 ms 1992 KB Output is correct
11 Correct 2600 ms 1996 KB Output is correct
12 Correct 3146 ms 2460 KB Output is correct
13 Correct 2971 ms 1996 KB Output is correct
14 Correct 1412 ms 1724 KB Output is correct
15 Correct 2065 ms 2084 KB Output is correct
16 Correct 4646 ms 2944 KB Output is correct
17 Correct 6426 ms 4056 KB Output is correct
18 Correct 5912 ms 3252 KB Output is correct
19 Correct 5592 ms 2892 KB Output is correct
20 Correct 6396 ms 4008 KB Output is correct
21 Correct 6249 ms 3688 KB Output is correct
22 Correct 5792 ms 2848 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 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 432 KB Output is correct
7 Correct 713 ms 1200 KB Output is correct
8 Correct 1087 ms 1400 KB Output is correct
9 Correct 2547 ms 2372 KB Output is correct
10 Correct 2796 ms 1992 KB Output is correct
11 Correct 2600 ms 1996 KB Output is correct
12 Correct 3146 ms 2460 KB Output is correct
13 Correct 2971 ms 1996 KB Output is correct
14 Correct 1412 ms 1724 KB Output is correct
15 Correct 2065 ms 2084 KB Output is correct
16 Correct 4646 ms 2944 KB Output is correct
17 Correct 6426 ms 4056 KB Output is correct
18 Correct 5912 ms 3252 KB Output is correct
19 Correct 5592 ms 2892 KB Output is correct
20 Correct 6396 ms 4008 KB Output is correct
21 Correct 6249 ms 3688 KB Output is correct
22 Correct 5792 ms 2848 KB Output is correct
23 Execution timed out 9053 ms 5996 KB Time limit exceeded
24 Halted 0 ms 0 KB -