oj.uz

Submission #800832

# Submission time Handle Problem Language Result Execution time Memory
800832 2023-08-01T23:41:57 Z PanosPask Dancing Elephants (IOI11_elephants) C++14
97 / 100
 9000 ms 5956 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 = 333;

    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 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 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 0 ms 212 KB Output is correct
7 Correct 1213 ms 1236 KB Output is correct
8 Correct 1430 ms 1456 KB Output is correct
9 Correct 2578 ms 2484 KB Output is correct
10 Correct 2635 ms 2032 KB Output is correct
11 Correct 2505 ms 2004 KB Output is correct
12 Correct 3360 ms 2652 KB Output is correct
13 Correct 2776 ms 2004 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 0 ms 212 KB Output is correct
7 Correct 1213 ms 1236 KB Output is correct
8 Correct 1430 ms 1456 KB Output is correct
9 Correct 2578 ms 2484 KB Output is correct
10 Correct 2635 ms 2032 KB Output is correct
11 Correct 2505 ms 2004 KB Output is correct
12 Correct 3360 ms 2652 KB Output is correct
13 Correct 2776 ms 2004 KB Output is correct
14 Correct 1527 ms 1652 KB Output is correct
15 Correct 2198 ms 1952 KB Output is correct
16 Correct 5112 ms 2992 KB Output is correct
17 Correct 7051 ms 4040 KB Output is correct
18 Correct 6156 ms 3064 KB Output is correct
19 Correct 5212 ms 2716 KB Output is correct
20 Correct 6842 ms 3996 KB Output is correct
21 Correct 6282 ms 3288 KB Output is correct
22 Correct 5323 ms 2644 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 0 ms 212 KB Output is correct
7 Correct 1213 ms 1236 KB Output is correct
8 Correct 1430 ms 1456 KB Output is correct
9 Correct 2578 ms 2484 KB Output is correct
10 Correct 2635 ms 2032 KB Output is correct
11 Correct 2505 ms 2004 KB Output is correct
12 Correct 3360 ms 2652 KB Output is correct
13 Correct 2776 ms 2004 KB Output is correct
14 Correct 1527 ms 1652 KB Output is correct
15 Correct 2198 ms 1952 KB Output is correct
16 Correct 5112 ms 2992 KB Output is correct
17 Correct 7051 ms 4040 KB Output is correct
18 Correct 6156 ms 3064 KB Output is correct
19 Correct 5212 ms 2716 KB Output is correct
20 Correct 6842 ms 3996 KB Output is correct
21 Correct 6282 ms 3288 KB Output is correct
22 Correct 5323 ms 2644 KB Output is correct
23 Execution timed out 9028 ms 5956 KB Time limit exceeded
24 Halted 0 ms 0 KB -