oj.uz

Submission #809089

# Submission time Handle Problem Language Result Execution time Memory
809089 2023-08-05T16:38:17 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 5844 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 = 450;

    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 == 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 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 340 KB Output is correct
5 Correct 1 ms 248 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 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 340 KB Output is correct
5 Correct 1 ms 248 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 635 ms 1236 KB Output is correct
8 Correct 914 ms 1336 KB Output is correct
9 Correct 2420 ms 2260 KB Output is correct
10 Correct 2423 ms 2292 KB Output is correct
11 Correct 2424 ms 2212 KB Output is correct
12 Correct 2879 ms 2524 KB Output is correct
13 Correct 2573 ms 2160 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 340 KB Output is correct
5 Correct 1 ms 248 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 635 ms 1236 KB Output is correct
8 Correct 914 ms 1336 KB Output is correct
9 Correct 2420 ms 2260 KB Output is correct
10 Correct 2423 ms 2292 KB Output is correct
11 Correct 2424 ms 2212 KB Output is correct
12 Correct 2879 ms 2524 KB Output is correct
13 Correct 2573 ms 2160 KB Output is correct
14 Correct 1229 ms 1752 KB Output is correct
15 Correct 1555 ms 1780 KB Output is correct
16 Correct 4022 ms 2788 KB Output is correct
17 Correct 5314 ms 3492 KB Output is correct
18 Correct 5365 ms 3500 KB Output is correct
19 Correct 4545 ms 2996 KB Output is correct
20 Correct 5215 ms 3344 KB Output is correct
21 Correct 5302 ms 3252 KB Output is correct
22 Correct 4788 ms 2864 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 340 KB Output is correct
5 Correct 1 ms 248 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 635 ms 1236 KB Output is correct
8 Correct 914 ms 1336 KB Output is correct
9 Correct 2420 ms 2260 KB Output is correct
10 Correct 2423 ms 2292 KB Output is correct
11 Correct 2424 ms 2212 KB Output is correct
12 Correct 2879 ms 2524 KB Output is correct
13 Correct 2573 ms 2160 KB Output is correct
14 Correct 1229 ms 1752 KB Output is correct
15 Correct 1555 ms 1780 KB Output is correct
16 Correct 4022 ms 2788 KB Output is correct
17 Correct 5314 ms 3492 KB Output is correct
18 Correct 5365 ms 3500 KB Output is correct
19 Correct 4545 ms 2996 KB Output is correct
20 Correct 5215 ms 3344 KB Output is correct
21 Correct 5302 ms 3252 KB Output is correct
22 Correct 4788 ms 2864 KB Output is correct
23 Execution timed out 9070 ms 5844 KB Time limit exceeded
24 Halted 0 ms 0 KB -