oj.uz

Submission #809090

# Submission time Handle Problem Language Result Execution time Memory
809090 2023-08-05T16:40:10 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 6112 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 = 300;

    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 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 0 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 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 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 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 709 ms 1264 KB Output is correct
8 Correct 944 ms 1396 KB Output is correct
9 Correct 2693 ms 2364 KB Output is correct
10 Correct 2906 ms 2340 KB Output is correct
11 Correct 2819 ms 2228 KB Output is correct
12 Correct 3260 ms 2524 KB Output is correct
13 Correct 3004 ms 2300 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 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 709 ms 1264 KB Output is correct
8 Correct 944 ms 1396 KB Output is correct
9 Correct 2693 ms 2364 KB Output is correct
10 Correct 2906 ms 2340 KB Output is correct
11 Correct 2819 ms 2228 KB Output is correct
12 Correct 3260 ms 2524 KB Output is correct
13 Correct 3004 ms 2300 KB Output is correct
14 Correct 1418 ms 1820 KB Output is correct
15 Correct 1797 ms 1784 KB Output is correct
16 Correct 4805 ms 2788 KB Output is correct
17 Correct 6236 ms 3400 KB Output is correct
18 Correct 6709 ms 3372 KB Output is correct
19 Correct 5644 ms 3168 KB Output is correct
20 Correct 5926 ms 3400 KB Output is correct
21 Correct 5834 ms 3360 KB Output is correct
22 Correct 6071 ms 3296 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 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 709 ms 1264 KB Output is correct
8 Correct 944 ms 1396 KB Output is correct
9 Correct 2693 ms 2364 KB Output is correct
10 Correct 2906 ms 2340 KB Output is correct
11 Correct 2819 ms 2228 KB Output is correct
12 Correct 3260 ms 2524 KB Output is correct
13 Correct 3004 ms 2300 KB Output is correct
14 Correct 1418 ms 1820 KB Output is correct
15 Correct 1797 ms 1784 KB Output is correct
16 Correct 4805 ms 2788 KB Output is correct
17 Correct 6236 ms 3400 KB Output is correct
18 Correct 6709 ms 3372 KB Output is correct
19 Correct 5644 ms 3168 KB Output is correct
20 Correct 5926 ms 3400 KB Output is correct
21 Correct 5834 ms 3360 KB Output is correct
22 Correct 6071 ms 3296 KB Output is correct
23 Execution timed out 9030 ms 6112 KB Time limit exceeded
24 Halted 0 ms 0 KB -