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Submission #600042

# Submission time Handle Problem Language Result Execution time Memory
600042 2022-07-20T12:08:01 Z MilosMilutinovic Dancing Elephants (IOI11_elephants) C++14
50 / 100
 4140 ms 3920 KB 
/**
 *    author:  wxhtzdy
 *    created: 20.07.2022 11:59:55
**/
#include "elephants.h"
#include <bits/stdc++.h>

using namespace std;

const int N = 150005;
const int BLOCK = sqrt(N);

int n, l, x[N], cnt[N], pos[N];
int id[N], order[N];

vector<int> idx[N / BLOCK];

void BuildBlock(int i) {
  sort(idx[i].begin(), idx[i].end(), [&](int a, int b) {
    if (x[a] != x[b]) {
      return x[a] < x[b];
    } else {
      return a < b;
    }
  });
  int sz = (int) idx[i].size();
  int ptr = sz - 1;    
  for (int j = sz - 1; j >= 0; j--) {
    if (x[idx[i][sz - 1]] - x[idx[i][j]] <= l) {
      cnt[idx[i][j]] = 1;
      pos[idx[i][j]] = x[idx[i][j]] + l;
    } else { 
      while (x[idx[i][ptr]] - x[idx[i][j]] > l) {
        ptr -= 1;
      }
      cnt[idx[i][j]] = cnt[idx[i][ptr + 1]] + 1;
      pos[idx[i][j]] = pos[idx[i][ptr + 1]];
    }                              
  }
}

void Build() {     
  for (int i = 0; i < n; i++) {
    order[i] = i;
  }
  sort(order, order + n, [&](int i, int j) {
    if (x[i] != x[j]) {
      return x[i] < x[j];
    } else {
      return i < j;
    }
  });
  for (int i = 0; i <= n / BLOCK; i++) {
    idx[i].clear();
  }
  for (int i = 0; i < n; i++) {
    id[order[i]] = i / BLOCK;
    idx[id[order[i]]].push_back(order[i]);
  }
  for (int i = 0; i <= n / BLOCK; i++) {
    BuildBlock(i);
  }
}

int Q;

int update(int i, int y) {
  ++Q;
  x[i] = y;
  if (Q == BLOCK / 5) {
    Build();
    Q = 0;
  } else {
    vector<int> b;
    bool found = false;
    for (int j = 0; j < (int) idx[id[i]].size(); j++) {
      if (idx[id[i]][j] != i) {      
        b.push_back(idx[id[i]][j]);
      } else {
        found = true;
      }
    }
    assert(found);
    idx[id[i]] = b;
    BuildBlock(id[i]);
    b.clear();
    for (int j = n / BLOCK; j >= 0; j--) {
      if (!idx[j].empty() && x[idx[j][0]] <= y) {
        id[i] = j;
        break;
      } 
    }        
    if (idx[id[i]].empty() || x[idx[id[i]].back()] < y) {
      idx[id[i]].push_back(i);
    } else {
      vector<int> b;    
      for (int j = 0; j < (int) idx[id[i]].size(); j++) {
        if (y <= x[idx[id[i]][j]]) {
          b.push_back(i);
          y = (int) 1.01e9;
          j -= 1;
        } else {
          b.push_back(idx[id[i]][j]);
        }
      }
      idx[id[i]] = b;
    }
    BuildBlock(id[i]);
  } 
  //Build(); // brute force check
  int ans = 0, R = -1;
  for (int i = 0; i <= n / BLOCK; i++) {
    if (idx[i].empty() || x[idx[i].back()] <= R) {
      continue;
    }                                          
    int low = 0, high = (int) idx[i].size() - 1, at = 0;
    while (low <= high) {
      int mid = low + high >> 1;
      if (x[idx[i][mid]] > R) {
        at = mid;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
    ans += cnt[idx[i][at]];
    R = pos[idx[i][at]];
  }       
  return ans; 
}

void init(int n, int l, int x[]) {
  ::n = n;
  ::l = l;
  for (int i = 0; i < n; i++) {
    ::x[i] = x[i];
  }
  Build();
}

Compilation message

elephants.cpp: In function 'int update(int, int)':
elephants.cpp:118:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  118 |       int mid = low + high >> 1;
      |                 ~~~~^~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct

Subtask #2
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 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 1 ms 340 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 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 1 ms 340 KB Output is correct
7 Correct 1201 ms 2204 KB Output is correct
8 Correct 1323 ms 2436 KB Output is correct
9 Correct 2208 ms 3920 KB Output is correct
10 Correct 2448 ms 3696 KB Output is correct
11 Correct 2458 ms 3640 KB Output is correct
12 Correct 4140 ms 3796 KB Output is correct
13 Correct 2459 ms 3564 KB Output is correct

Subtask #4
0 / 47.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 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 1 ms 340 KB Output is correct
7 Correct 1201 ms 2204 KB Output is correct
8 Correct 1323 ms 2436 KB Output is correct
9 Correct 2208 ms 3920 KB Output is correct
10 Correct 2448 ms 3696 KB Output is correct
11 Correct 2458 ms 3640 KB Output is correct
12 Correct 4140 ms 3796 KB Output is correct
13 Correct 2459 ms 3564 KB Output is correct
14 Incorrect 1776 ms 3180 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #5
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 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 1 ms 340 KB Output is correct
7 Correct 1201 ms 2204 KB Output is correct
8 Correct 1323 ms 2436 KB Output is correct
9 Correct 2208 ms 3920 KB Output is correct
10 Correct 2448 ms 3696 KB Output is correct
11 Correct 2458 ms 3640 KB Output is correct
12 Correct 4140 ms 3796 KB Output is correct
13 Correct 2459 ms 3564 KB Output is correct
14 Incorrect 1776 ms 3180 KB Output isn't correct
15 Halted 0 ms 0 KB -