Submission #106334

#	Time	Username	Problem	Language	Result	Execution time	Memory
106334		RezwanArefin01	Dancing Elephants (IOI11_elephants)	C++17	26 / 100	20 ms	1320 KiB

elephants

#include <bits/stdc++.h>
#include "elephants.h"
using namespace std; 

const int N = 150001; 
const int sz = 1000; 
const int K = N / sz + 2; 

int n, L, f[K][sz], g[K][sz], B, X[N], st[K], query; 
vector<int> block[K]; 

void build(int k) {
	int m = block[k].size() - 1; 
	f[k][m] = 0; 
	g[k][m] = block[k].back(); 
	for(int i = m - 1, t = m; i >= 0; --i) {
		while(block[k][i] + L < block[k][t]) --t; ++t; 
		f[k][i] = f[k][t] + 1;
		g[k][i] = t == m ? block[k][i] + L + 1 : g[k][t]; 
	}
}

void rebuild() {
	vector<int> v; 
	for(int i = 0; i < B; ++i) {
		for(int j = 0; j < block[i].size() - 1; ++j) 
			v.push_back(block[i][j]);
	}
	for(int i = 0; i < n; ++i) 
		block[i / sz].push_back(v[i]); 
	for(int k = 0; k < B; ++k) if(block[k].size()) {
		block[k].push_back(block[k].back() + L + 1); 
		build(k); 
		st[k] = block[k][0]; 
	}
}

void init(int _n, int _L, int _X[]) {
	n = _n; L = _L; B = 0; 
	for(int i = 0; i < n; ++i) {
		block[i / sz].push_back(X[i] = _X[i]); 
		if(i % sz == 0) ++B; 
	}
	for(int k = 0; k < B; ++k) if(block[k].size()) {
		block[k].push_back(block[k].back() + L + 1); 
		build(k); 
		st[k] = block[k][0]; 
	} 
}

int answer() {
	int cur = -1e9, ans = 0; 
	for(int i = 0; i < B; ++i) {
		int j = lower_bound(block[i].begin(), block[i].end(), cur) - block[i].begin();
		if(j >= block[i].size()) continue; 
		ans += f[i][j]; 
		cur = g[i][j]; 
	} return ans; 
}

int find(int x) { 
	int i = lower_bound(st, st + B, x) - st;
	if(i >= B) --i;
	return i;  
}

int update(int k, int y) {
	if(++query % sz == 0) rebuild(); 

	int lb = find(X[k]);  
	int rb = find(y); 

	int pos = lower_bound(block[lb].begin(), block[lb].end(), X[k]) - block[lb].begin(); 
	X[k] = y; 

	for(int i = pos; i < block[lb].size() - 1; ++i) 
		swap(block[lb][i], block[lb][i + 1]); 

	block[lb].pop_back(); block[lb].pop_back(); 
	block[lb].push_back(block[lb].back() + L + 1); 


	block[rb].pop_back(); block[rb].push_back(y); 
	for(int i = block[rb].size() - 1; i >= 1; --i) {
		if(block[rb][i - 1] > block[rb][i]) {
			swap(block[rb][i], block[rb][i - 1]); 
		} else break; 
	}
	block[rb].push_back(block[rb].back() + L + 1); 

	build(lb); 
	if(lb != rb) build(rb); 

	return answer(); 
}

Compilation message (stderr)

elephants.cpp: In function 'void build(int)':
elephants.cpp:17:3: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
   while(block[k][i] + L < block[k][t]) --t; ++t; 
   ^~~~~
elephants.cpp:17:45: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
   while(block[k][i] + L < block[k][t]) --t; ++t; 
                                             ^~
elephants.cpp: In function 'void rebuild()':
elephants.cpp:26:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < block[i].size() - 1; ++j) 
                  ~~^~~~~~~~~~~~~~~~~~~~~
elephants.cpp: In function 'int answer()':
elephants.cpp:55:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(j >= block[i].size()) continue; 
      ~~^~~~~~~~~~~~~~~~~~
elephants.cpp: In function 'int update(int, int)':
elephants.cpp:76:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = pos; i < block[lb].size() - 1; ++i) 
                   ~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 0 / 24
• Subtask 4: 0 / 47
• Subtask 5: 0 / 3