oj.uz

Submission #575311

# Submission time Handle Problem Language Result Execution time Memory
575311 2022-06-10T07:23:56 Z ktkerem Ball Machine (BOI13_ballmachine) C++17
100 / 100
 176 ms 22328 KB 
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
#include <queue>
#include <utility>
using namespace std;

// full solution
// (author: simon buerger)

void readTree(int n, vector<int>& nodes)
{
	nodes.resize(n);
	for(int i = 0; i < n; ++i)
	{
		scanf("%d", &nodes[i]);
		nodes[i]--;
		if(nodes[i] == -1)
			nodes[i] = i;
	}
}

#define LOGN 17	// will work for n <= 100.000
int n, q;
vector<int> par[LOGN];
vector<vector<int> > g;
vector<int> low;
vector<int> post;
vector<bool> ball;
vector<int> layer;	// root is at 0
int root;
bool cmpLow(int a, int b) { return low[a] < low[b]; }
bool cmpPostInv(int a, int b) { return post[a] > post[b]; }
priority_queue<int, vector<int>, bool(*)(int,int)> pepsi(cmpPostInv);
vector<int> full;	// not ordered in any sense

void dfsLow(int v)
{
	if(v == root)
		layer[v] = 0;
	else
		layer[v] = 1 + layer[par[0][v]];

	low[v] = v;
	for(int i = 0; i < (int)g[v].size(); ++i)
	{
		int w = g[v][i];
		dfsLow(w);
		low[v] = min(low[v], low[w]);
	}
}

void dfsPost(int v)
{
	static int time = 0;
	for(int i = 0; i < (int)g[v].size(); ++i)
		dfsPost(g[v][i]);
	post[v] = time++;
}

int add()	// return pos
{
	int k = pepsi.top();
	pepsi.pop();
	ball[k] = true;
	return k;
}

int remove(int pos)	// return position of actual remove
{
	if(!ball[pos])
		cerr << "ERROR: remove from pepsi node" << endl;
	//cerr << "remove " << pos;
	for(int level = LOGN-1; level >= 0; --level)
		if(ball[par[level][pos]])
			pos = par[level][pos];

	ball[pos] = false;
	pepsi.push(pos);
	//cerr << " actual = " << pos << endl;
	return pos;
}

int main(int argc, char** argv)
{
	scanf("%d %d", &n, &q);

	g.resize(n);
	for(int i = 0; i < LOGN; ++i)
		par[i].resize(n);
	ball.resize(n, false);
	low.resize(n);
	post.resize(n);
	layer.resize(n);

	readTree(n, par[0]);

	for(int i = 0; i < n; ++i)
		if(par[0][i] == i)
			root = i;
		else
			g[par[0][i]].push_back(i);

	par[0][root] = root;
	for(int level = 1; level < LOGN; ++level)
		for(int i = 0; i < n; ++i)
			par[level][i] = par[level-1][par[level-1][i]];

	dfsLow(root);
	for(int i = 0; i < n; ++i)
		sort(g[i].begin(), g[i].end(), cmpLow);

	dfsPost(root);
	for(int i = 0; i < n; ++i)
		pepsi.push(i);

	for(int i = 0; i < q; ++i)
	{
		int t, k;
		scanf("%d %d", &t, &k);

		if(t == 1)	// add k balls
		{
			for(int j = 0; j < k; ++j)
			{
				int pos = add();
				if(j+1 == k)
					printf("%d\n", pos+1);
			}
		}
		else if(t == 2)	// remove one ball from position k
		{
			--k;
			int actual = remove(k);
			printf("%d\n", layer[k]-layer[actual]);
		}
		else cerr << "ERROR: invalid t" << endl;
	}
}

Compilation message

ballmachine.cpp: In function 'void readTree(int, std::vector<int>&)':
ballmachine.cpp:18:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |   scanf("%d", &nodes[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~
ballmachine.cpp: In function 'int main(int, char**)':
ballmachine.cpp:88:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |  scanf("%d %d", &n, &q);
      |  ~~~~~^~~~~~~~~~~~~~~~~
ballmachine.cpp:122:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |   scanf("%d %d", &t, &k);
      |   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 103 ms 9124 KB Output is correct
3 Correct 64 ms 9168 KB Output is correct
4 Correct 1 ms 288 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 5 ms 852 KB Output is correct
10 Correct 17 ms 2392 KB Output is correct
11 Correct 86 ms 9140 KB Output is correct
12 Correct 62 ms 9168 KB Output is correct
13 Correct 87 ms 9072 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 4812 KB Output is correct
2 Correct 128 ms 17644 KB Output is correct
3 Correct 91 ms 12888 KB Output is correct
4 Correct 64 ms 5732 KB Output is correct
5 Correct 54 ms 5936 KB Output is correct
6 Correct 51 ms 5964 KB Output is correct
7 Correct 54 ms 5100 KB Output is correct
8 Correct 38 ms 4824 KB Output is correct
9 Correct 124 ms 17296 KB Output is correct
10 Correct 141 ms 17624 KB Output is correct
11 Correct 112 ms 17572 KB Output is correct
12 Correct 121 ms 15764 KB Output is correct
13 Correct 85 ms 19572 KB Output is correct
14 Correct 72 ms 12896 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 52 ms 9256 KB Output is correct
2 Correct 154 ms 15580 KB Output is correct
3 Correct 108 ms 17696 KB Output is correct
4 Correct 84 ms 13804 KB Output is correct
5 Correct 87 ms 14056 KB Output is correct
6 Correct 94 ms 14148 KB Output is correct
7 Correct 91 ms 12276 KB Output is correct
8 Correct 105 ms 17664 KB Output is correct
9 Correct 130 ms 17476 KB Output is correct
10 Correct 161 ms 17788 KB Output is correct
11 Correct 140 ms 17756 KB Output is correct
12 Correct 176 ms 15552 KB Output is correct
13 Correct 161 ms 22328 KB Output is correct
14 Correct 102 ms 13288 KB Output is correct

Subtask #4
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 171 ms 17516 KB Output is correct
2 Correct 140 ms 16192 KB Output is correct
3 Correct 96 ms 21956 KB Output is correct
4 Correct 172 ms 17552 KB Output is correct
5 Correct 135 ms 17744 KB Output is correct
6 Correct 110 ms 17704 KB Output is correct
7 Correct 146 ms 16132 KB Output is correct
8 Correct 109 ms 21912 KB Output is correct
9 Correct 68 ms 12932 KB Output is correct