oj.uz

Submission #600155

# Submission time Handle Problem Language Result Execution time Memory
600155 2022-07-20T13:47:25 Z MilosMilutinovic Dancing Elephants (IOI11_elephants) C++14
50 / 100
 9000 ms 5096 KB 
/**
 *    author:  wxhtzdy
 *    created: 20.07.2022 11:59:55
**/
#include "elephants.h"
#include <bits/stdc++.h>

using namespace std;

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

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

vector<int> idx[MAX / BLOCK + 5];

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--) {
    assert(id[idx[i][j]] == i);
    if (j + 1 < sz) {
      assert(x[idx[i][j]] <= x[idx[i][j + 1]]);
    }
    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;

bool first = true;

int update(int i, int y) {
  ++Q;
  x[i] = y;
  if (Q == BLOCK / 7) {
    Build();
    Q = 0;
    int lst = -1;       
    for (int j = 0; j <= n / BLOCK; j++) {
      if (idx[j].empty()) {
        continue;
      }
      assert(lst <= x[idx[j][0]]);
      lst = x[idx[j].back()];
    }
  } 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();
    int lst = -1;       
    for (int j = 0; j <= n / BLOCK; j++) {
      if (idx[j].empty()) {
        continue;
      }
      assert(lst <= x[idx[j][0]]);
      lst = x[idx[j].back()];
    }
    id[i] = 0;
    for (int j = n / BLOCK; j >= 0; j--) {
      if (!idx[j].empty() && x[idx[j][0]] <= x[i]) {
        id[i] = j;
        break;
      } 
    }        
    idx[id[i]].push_back(i);
    /*if (idx[id[i]].empty() || x[idx[id[i]].back()] < y) {
    } 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]);
    lst = -1;       
    for (int j = 0; j <= n / BLOCK; j++) {
      if (idx[j].empty()) {
        continue;
      }        
      assert(x[idx[j][0]] <= x[idx[j].back()]);
      lst = x[idx[j].back()];
    }
  } 
  //Build(); // brute force check
  int ans = 0, R = -1;
  for (int j = 0; j <= n / BLOCK; j++) {
    if (idx[j].empty() || x[idx[j].back()] <= R) {
      continue;
    }                                          
    int low = 0, high = (int) idx[j].size() - 1, at = 0;
    while (low <= high) {
      int mid = low + high >> 1;
      if (x[idx[j][mid]] > R) {
        at = mid;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
    assert(R < x[idx[j][at]] && (at == 0 || R >= x[idx[j][at - 1]]));
    ans += cnt[idx[j][at]];
    R = pos[idx[j][at]];
  }
  if (false) {
    for (int i = 0; i < n; i++) {
      order[i] = i;
    }
    sort(order, order + n, [&](int i, int j) {
      return x[i] < x[j];
    });     
    int nans = 0;
    for (int i = 0; i < n; i++) {
      int ptr = i;
      while (ptr + 1 < n && x[order[ptr + 1]] <= x[order[i]] + l) {
        ptr += 1;
      }
      i = ptr;
      nans += 1;
    }
    assert(nans == ans);
    first = false;
  }  
  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();
  int lst = -1;       
  for (int j = 0; j <= n / BLOCK; j++) {
    if (idx[j].empty()) {
      continue;
    }
    assert(lst <= x[idx[j][0]]);
    lst = x[idx[j].back()];
  }
}

Compilation message

elephants.cpp: In function 'int update(int, int)':
elephants.cpp:149:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  149 |       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 0 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 0 ms 340 KB Output is correct
7 Correct 1660 ms 1292 KB Output is correct
8 Correct 1871 ms 1428 KB Output is correct
9 Correct 3085 ms 2356 KB Output is correct
10 Correct 3251 ms 2360 KB Output is correct
11 Correct 3328 ms 2356 KB Output is correct
12 Correct 5766 ms 2356 KB Output is correct
13 Correct 3296 ms 2356 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 0 ms 340 KB Output is correct
7 Correct 1660 ms 1292 KB Output is correct
8 Correct 1871 ms 1428 KB Output is correct
9 Correct 3085 ms 2356 KB Output is correct
10 Correct 3251 ms 2360 KB Output is correct
11 Correct 3328 ms 2356 KB Output is correct
12 Correct 5766 ms 2356 KB Output is correct
13 Correct 3296 ms 2356 KB Output is correct
14 Correct 3246 ms 1672 KB Output is correct
15 Correct 2983 ms 3244 KB Output is correct
16 Correct 8318 ms 4412 KB Output is correct
17 Execution timed out 9041 ms 5096 KB Time limit exceeded
18 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 0 ms 340 KB Output is correct
7 Correct 1660 ms 1292 KB Output is correct
8 Correct 1871 ms 1428 KB Output is correct
9 Correct 3085 ms 2356 KB Output is correct
10 Correct 3251 ms 2360 KB Output is correct
11 Correct 3328 ms 2356 KB Output is correct
12 Correct 5766 ms 2356 KB Output is correct
13 Correct 3296 ms 2356 KB Output is correct
14 Correct 3246 ms 1672 KB Output is correct
15 Correct 2983 ms 3244 KB Output is correct
16 Correct 8318 ms 4412 KB Output is correct
17 Execution timed out 9041 ms 5096 KB Time limit exceeded
18 Halted 0 ms 0 KB -