oj.uz

Submission #809091

# Submission time Handle Problem Language Result Execution time Memory
809091 2023-08-05T16:43:15 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 6048 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 = 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)
{
    // After some updates, rebuild
    upd++;
    if (upd == 2 * BLOCK_SIZE) {
        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 1 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 1 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 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 212 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 340 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 706 ms 1296 KB Output is correct
8 Correct 1180 ms 1424 KB Output is correct
9 Correct 2500 ms 2136 KB Output is correct
10 Correct 2715 ms 2308 KB Output is correct
11 Correct 2534 ms 2364 KB Output is correct
12 Correct 2874 ms 2580 KB Output is correct
13 Correct 2878 ms 2272 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 340 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 706 ms 1296 KB Output is correct
8 Correct 1180 ms 1424 KB Output is correct
9 Correct 2500 ms 2136 KB Output is correct
10 Correct 2715 ms 2308 KB Output is correct
11 Correct 2534 ms 2364 KB Output is correct
12 Correct 2874 ms 2580 KB Output is correct
13 Correct 2878 ms 2272 KB Output is correct
14 Correct 1570 ms 1904 KB Output is correct
15 Correct 1786 ms 1772 KB Output is correct
16 Correct 4208 ms 2712 KB Output is correct
17 Correct 6017 ms 3684 KB Output is correct
18 Correct 6071 ms 3564 KB Output is correct
19 Correct 5471 ms 3180 KB Output is correct
20 Correct 5888 ms 3556 KB Output is correct
21 Correct 6057 ms 3652 KB Output is correct
22 Correct 5806 ms 3380 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 340 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 706 ms 1296 KB Output is correct
8 Correct 1180 ms 1424 KB Output is correct
9 Correct 2500 ms 2136 KB Output is correct
10 Correct 2715 ms 2308 KB Output is correct
11 Correct 2534 ms 2364 KB Output is correct
12 Correct 2874 ms 2580 KB Output is correct
13 Correct 2878 ms 2272 KB Output is correct
14 Correct 1570 ms 1904 KB Output is correct
15 Correct 1786 ms 1772 KB Output is correct
16 Correct 4208 ms 2712 KB Output is correct
17 Correct 6017 ms 3684 KB Output is correct
18 Correct 6071 ms 3564 KB Output is correct
19 Correct 5471 ms 3180 KB Output is correct
20 Correct 5888 ms 3556 KB Output is correct
21 Correct 6057 ms 3652 KB Output is correct
22 Correct 5806 ms 3380 KB Output is correct
23 Execution timed out 9033 ms 6048 KB Time limit exceeded
24 Halted 0 ms 0 KB -