oj.uz

Submission #59115

# Submission time Handle Problem Language Result Execution time Memory
59115 2018-07-20T14:59:09 Z fallingstar Dancing Elephants (IOI11_elephants) C++14
100 / 100
 5571 ms 10692 KB 
#include "elephants.h"
#include <cassert>
#include <algorithm>
#include <vector>

using namespace std;

const int N = 1.5e5;

int n, L;

struct TElephant { 
	int id, x;
	int f, xDest;
	inline bool operator < (const TElephant &b) const 
	{
		return x < b.x || (x == b.x && id < b.id);			// if x equals, compare by id
	}
}; 

vector<vector<TElephant> > a;
int pos[N];

const int BLOCK_SIZE = 700;

void Calc(vector<TElephant> &seg)
{
	auto itR = prev(seg.end()), itL = itR;
	itL->f = 0, itL->xDest = itL->x;
	while (itL != seg.begin())
	{
		--itL;
		while (itR != itL && itL->x + L < prev(itR)->x) itR = prev(itR);
		if (itL->x + L < itR->x)
		{
			itL->f = itR->f + 1;
			itL->xDest = itR->xDest;
		}
		else 
			itL->f = 0, itL->xDest = itL->x;
	}
}

pair<int, int> arr[N];

void Rebuild()
{
	int m = 0;
	for (const auto &seg: a)
		for (const auto &e: seg)
			arr[m++] = {e.id, e.x};
	
	a.clear();
	vector<TElephant> cur;
	for (int i = 0; i < n; ++i)
	{
		cur.push_back({arr[i].first, arr[i].second, 0, arr[i].second});
		if (cur.size() >= BLOCK_SIZE || i == n - 1) 
		{
			Calc(cur);
			a.push_back(move(cur));
			cur.clear();
		}
	}
}

void init(int numElephants, int camWidth, int X[])
{
	n = numElephants;
	L = camWidth;
	vector<TElephant> sentinel;
	for (int i = 0; i < n; ++i) 
	{
		pos[i] = X[i];
		sentinel.push_back({i, X[i], 0, 0});
	}
	a.push_back(move(sentinel));
	Rebuild();
}

const int STACK_SIZE = 400;
int countQuery = 0;

int GetAns() 
{
	int ans = 0, curX = a.begin()->begin()->x;
	for (auto i = a.begin(); i != a.end(); ++i)
		if (prev(i->end())->x >= curX)					// if segment contain current X
		{
			auto it = lower_bound(i->begin(), i->end(), curX, [](const TElephant &p, int q) { 
				return p.x < q;
			});
			ans += it->f + 1;					// jump inner-segment, then to new segment
			curX = it->xDest + L + 1;	
		}
	return ans;
}

int update(int idx, int y)
{
	int x = pos[idx];
	TElephant old_ele {idx, x, 0, 0};
	TElephant new_ele {idx, y, 0, 0};
	
	// erase idx from old position
	{
		auto i = lower_bound(a.begin(), a.end(), old_ele, [](const vector<TElephant> &p, TElephant q) {
			return p.back() < q;
		});
		vector<TElephant> leftSeg;
		auto it = lower_bound(i->begin(), i->end(), old_ele);
		
		// cut segment into 2 parts
		leftSeg = vector<TElephant>(i->begin(), it);
		i->erase(i->begin(), next(it));
			
		if (i->empty()) i = a.erase(i);
		if (!leftSeg.empty()) 
		{
			Calc(leftSeg);
			a.insert(i, move(leftSeg));
		}
	}
	
	// insert idx to new position
	if (a.empty()) 
		a.push_back(vector<TElephant>(1, new_ele)); 
	else
	{
		auto i = lower_bound(a.begin(), a.end(), new_ele, [](const vector<TElephant> &p, TElephant q) {
			return p.back() < q;
		});
		// insert new elephant to its segment then recalculate the segment
		if (i != a.end())
		{
			auto it = lower_bound(i->begin(), i->end(), new_ele);
			i->insert(it, new_ele);
		}
		else
		{
			--i;
			i->push_back(new_ele);
		}
		Calc(*i);
	}
	pos[idx] = y;
	++countQuery;
	if (countQuery >= STACK_SIZE) Rebuild(), countQuery = 0;
	return GetAns();
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 248 KB Output is correct
2 Correct 2 ms 356 KB Output is correct
3 Correct 2 ms 392 KB Output is correct

Subtask #2
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 248 KB Output is correct
2 Correct 2 ms 356 KB Output is correct
3 Correct 2 ms 392 KB Output is correct
4 Correct 2 ms 536 KB Output is correct
5 Correct 2 ms 536 KB Output is correct
6 Correct 2 ms 536 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 248 KB Output is correct
2 Correct 2 ms 356 KB Output is correct
3 Correct 2 ms 392 KB Output is correct
4 Correct 2 ms 536 KB Output is correct
5 Correct 2 ms 536 KB Output is correct
6 Correct 2 ms 536 KB Output is correct
7 Correct 280 ms 1616 KB Output is correct
8 Correct 383 ms 2044 KB Output is correct
9 Correct 545 ms 3836 KB Output is correct
10 Correct 327 ms 3836 KB Output is correct
11 Correct 375 ms 3836 KB Output is correct
12 Correct 771 ms 4876 KB Output is correct
13 Correct 337 ms 4876 KB Output is correct

Subtask #4
47.0 / 47.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 248 KB Output is correct
2 Correct 2 ms 356 KB Output is correct
3 Correct 2 ms 392 KB Output is correct
4 Correct 2 ms 536 KB Output is correct
5 Correct 2 ms 536 KB Output is correct
6 Correct 2 ms 536 KB Output is correct
7 Correct 280 ms 1616 KB Output is correct
8 Correct 383 ms 2044 KB Output is correct
9 Correct 545 ms 3836 KB Output is correct
10 Correct 327 ms 3836 KB Output is correct
11 Correct 375 ms 3836 KB Output is correct
12 Correct 771 ms 4876 KB Output is correct
13 Correct 337 ms 4876 KB Output is correct
14 Correct 316 ms 4876 KB Output is correct
15 Correct 380 ms 4876 KB Output is correct
16 Correct 1141 ms 5196 KB Output is correct
17 Correct 1436 ms 6232 KB Output is correct
18 Correct 1454 ms 6488 KB Output is correct
19 Correct 863 ms 6488 KB Output is correct
20 Correct 1569 ms 6488 KB Output is correct
21 Correct 1593 ms 6488 KB Output is correct
22 Correct 677 ms 6488 KB Output is correct

Subtask #5
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 248 KB Output is correct
2 Correct 2 ms 356 KB Output is correct
3 Correct 2 ms 392 KB Output is correct
4 Correct 2 ms 536 KB Output is correct
5 Correct 2 ms 536 KB Output is correct
6 Correct 2 ms 536 KB Output is correct
7 Correct 280 ms 1616 KB Output is correct
8 Correct 383 ms 2044 KB Output is correct
9 Correct 545 ms 3836 KB Output is correct
10 Correct 327 ms 3836 KB Output is correct
11 Correct 375 ms 3836 KB Output is correct
12 Correct 771 ms 4876 KB Output is correct
13 Correct 337 ms 4876 KB Output is correct
14 Correct 316 ms 4876 KB Output is correct
15 Correct 380 ms 4876 KB Output is correct
16 Correct 1141 ms 5196 KB Output is correct
17 Correct 1436 ms 6232 KB Output is correct
18 Correct 1454 ms 6488 KB Output is correct
19 Correct 863 ms 6488 KB Output is correct
20 Correct 1569 ms 6488 KB Output is correct
21 Correct 1593 ms 6488 KB Output is correct
22 Correct 677 ms 6488 KB Output is correct
23 Correct 3935 ms 9840 KB Output is correct
24 Correct 3993 ms 10316 KB Output is correct
25 Correct 2838 ms 10316 KB Output is correct
26 Correct 2663 ms 10316 KB Output is correct
27 Correct 3261 ms 10316 KB Output is correct
28 Correct 666 ms 10316 KB Output is correct
29 Correct 643 ms 10316 KB Output is correct
30 Correct 738 ms 10316 KB Output is correct
31 Correct 610 ms 10316 KB Output is correct
32 Correct 3032 ms 10316 KB Output is correct
33 Correct 1772 ms 10316 KB Output is correct
34 Correct 2496 ms 10316 KB Output is correct
35 Correct 1838 ms 10316 KB Output is correct
36 Correct 2145 ms 10316 KB Output is correct
37 Correct 3984 ms 10600 KB Output is correct
38 Correct 2865 ms 10600 KB Output is correct
39 Correct 3430 ms 10600 KB Output is correct
40 Correct 2687 ms 10600 KB Output is correct
41 Correct 5537 ms 10692 KB Output is correct
42 Correct 5571 ms 10692 KB Output is correct