oj.uz

Submission #815592

# Submission time Handle Problem Language Result Execution time Memory
815592 2023-08-08T17:13:26 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 10820 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);

    int r = sz;
    for (int i = sz - 1; i >= 0; i--) {
        while (r > i + 1 && b.positions[r - 1] > b.positions[i] + L)
            r--;

        if (r == sz) {
            b.photos[i] = mp(b.positions[i] + L + 1, 1);
        }
        else {
            b.photos[i] = b.photos[r];
            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 = 500;

    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)
{
    // After some updates, rebuild
    upd++;
    if (upd == 490) {
        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;
    }

    // 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 'int update(int, int)':
elephants.cpp:178:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  178 |     for (int i = 0; i < blocks.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
elephants.cpp:188:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  188 |     for (int i = 0; i < blocks.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~
elephants.cpp:189:50: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  189 |         if (blocks[i].positions.back() >= y || i == blocks.size() - 1) {
      |                                                ~~^~~~~~~~~~~~~~~~~~~~
elephants.cpp:198:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Block>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  198 |     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 0 ms 212 KB Output is correct
3 Correct 0 ms 340 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 0 ms 212 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 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 0 ms 212 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 630 ms 2132 KB Output is correct
8 Correct 827 ms 2360 KB Output is correct
9 Correct 2188 ms 3780 KB Output is correct
10 Correct 2264 ms 3476 KB Output is correct
11 Correct 2237 ms 3480 KB Output is correct
12 Correct 2644 ms 3900 KB Output is correct
13 Correct 2377 ms 3328 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 0 ms 212 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 630 ms 2132 KB Output is correct
8 Correct 827 ms 2360 KB Output is correct
9 Correct 2188 ms 3780 KB Output is correct
10 Correct 2264 ms 3476 KB Output is correct
11 Correct 2237 ms 3480 KB Output is correct
12 Correct 2644 ms 3900 KB Output is correct
13 Correct 2377 ms 3328 KB Output is correct
14 Correct 1183 ms 3292 KB Output is correct
15 Correct 1506 ms 3244 KB Output is correct
16 Correct 3969 ms 4572 KB Output is correct
17 Correct 5445 ms 5428 KB Output is correct
18 Correct 5439 ms 5336 KB Output is correct
19 Correct 4391 ms 5144 KB Output is correct
20 Correct 5228 ms 5416 KB Output is correct
21 Correct 5259 ms 5244 KB Output is correct
22 Correct 4745 ms 4580 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 0 ms 212 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 630 ms 2132 KB Output is correct
8 Correct 827 ms 2360 KB Output is correct
9 Correct 2188 ms 3780 KB Output is correct
10 Correct 2264 ms 3476 KB Output is correct
11 Correct 2237 ms 3480 KB Output is correct
12 Correct 2644 ms 3900 KB Output is correct
13 Correct 2377 ms 3328 KB Output is correct
14 Correct 1183 ms 3292 KB Output is correct
15 Correct 1506 ms 3244 KB Output is correct
16 Correct 3969 ms 4572 KB Output is correct
17 Correct 5445 ms 5428 KB Output is correct
18 Correct 5439 ms 5336 KB Output is correct
19 Correct 4391 ms 5144 KB Output is correct
20 Correct 5228 ms 5416 KB Output is correct
21 Correct 5259 ms 5244 KB Output is correct
22 Correct 4745 ms 4580 KB Output is correct
23 Execution timed out 9082 ms 10820 KB Time limit exceeded
24 Halted 0 ms 0 KB -