Submission #897279

#	Time	Username	Problem	Language	Result	Execution time	Memory
897279		Mathias	Ball Machine (BOI13_ballmachine)	C++14	100 / 100	155 ms	31152 KiB

ballmachine

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5+7;
const int LOG = 19;
int jp[MAXN][LOG];
int ojciec[MAXN];
int depth[MAXN];
int mini[MAXN];
int post[MAXN];
bool ball[MAXN];
vector<int> g[MAXN];
set<pair<int,int> > s;
int cnt=0;
void DFS(int x){
	depth[x]=depth[ojciec[x]]+1;
	jp[x][0]=ojciec[x];
	for(int i=1;i<LOG;i++) jp[x][i]=jp[jp[x][i-1]][i-1];
	vector<pair<int,int> > vec;
	for(int i=0;i<g[x].size();i++) vec.push_back({mini[g[x][i]], g[x][i]});
	sort(vec.begin(),vec.end());
	for(int i=0;i<vec.size();i++) DFS(vec[i].second);
	//cout<<"x="<<x<<" cnt+1="<<cnt+1<<'\n';
	s.insert({++cnt,x});
	post[x]=cnt;
}
void DFS1(int x){
	for(int i=0;i<g[x].size();i++){
		DFS1(g[x][i]);
	}
	mini[x]=x;
	for(int i=0;i<g[x].size();i++) mini[x]=min(mini[x],mini[g[x][i]]);
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int n,q,x,r,a,b;
	pair<int,int> p;
	cin>>n>>q;
	for(int i=1;i<=n;i++){
		cin>>x;
		ojciec[i]=x;
		if(x==0) r=i;
		else g[x].push_back(i);
	}
	ojciec[r]=r;
	DFS1(r);
	DFS(r);	
	//for(int i=1;i<=n;i++) cout<<mini[i]<<' '; cout<<'\n';
	while(q--){
		cin>>a>>b;
		if(a==1){
			while(b--){
				auto it=s.begin();
				p=*it;
				//cout<<b<<' '<<p.first<<' '<<p.second<<'\n';
				ball[p.second]=1;
				if(b==0){
					cout<<p.second<<'\n';
				}
				s.erase(it);
			}
		}
		else{
			x=b;
			for(int i=LOG-1;i>=0;i--){
				if(ball[jp[x][i]]==1){
					x=jp[x][i];
				}	
			}
			ball[x]=0;
			s.insert({post[x],x});
			//cout<<b<<' '<<x<<'\n';
			cout<<depth[b]-depth[x]<<'\n';
		}
		//for(int i=1;i<=n;i++){
		//	cout<<ball[i]<<' ';
		//}
		//cout<<'\n';
		//for (auto it = s.begin(); it != s.end(); it++){
		//	p=*it;
		//	cout<<p.second<<' ';
		//} 
		//cout<<'\n';
	}
	return 0;
}

Compilation message (stderr)

ballmachine.cpp: In function 'void DFS(int)':
ballmachine.cpp:19:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |  for(int i=0;i<g[x].size();i++) vec.push_back({mini[g[x][i]], g[x][i]});
      |              ~^~~~~~~~~~~~
ballmachine.cpp:21:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for(int i=0;i<vec.size();i++) DFS(vec[i].second);
      |              ~^~~~~~~~~~~
ballmachine.cpp: In function 'void DFS1(int)':
ballmachine.cpp:27:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~
ballmachine.cpp:31:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |  for(int i=0;i<g[x].size();i++) mini[x]=min(mini[x],mini[g[x][i]]);
      |              ~^~~~~~~~~~~~
ballmachine.cpp: In function 'int main()':
ballmachine.cpp:46:5: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   46 |  DFS(r);
      |  ~~~^~~

• Subtask 1: 25 / 25
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40
• Subtask 4: 5 / 5