Submission #897175

#	Time	Username	Problem	Language	Result	Execution time	Memory
897175		Mathias	Ball Machine (BOI13_ballmachine)	C++14	8.57 / 100	1097 ms	26968 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];
bool ball[MAXN];
vector<int> g[MAXN];
set<pair<int,int> > s;
int post=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];
	for(int i=0;i<g[x].size();i++){
		DFS(g[x][i]);
	}
	s.insert({++post,x});
}
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);
	}
	DFS(r);
	while(q--){
		cin>>a>>b;
		if(a==1){
			while(b--){
				auto it=s.begin();
				s.erase(it);
				p=*it;
				ball[p.second]=1;
				if(b==0){
					cout<<p.second<<'\n';
				}
			}
		}
		else{
			x=b;
			for(int i=LOG-1;i>=0;i--){
				if(ball[jp[x][i]]==1){
					x=jp[x][i];
				}	
			}
			ball[x]=0;
			//cout<<b<<' '<<x<<'\n';
			cout<<depth[b]-depth[x]<<'\n';
		}
	}
	return 0;
}

Compilation message (stderr)

ballmachine.cpp: In function 'void DFS(int)':
ballmachine.cpp:16:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~
ballmachine.cpp: In function 'int main()':
ballmachine.cpp:32:5: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   32 |  DFS(r);
      |  ~~~^~~

• Subtask 1: 0 / 25
• Subtask 2: 0 / 30
• Subtask 3: 8.571428571428571 / 40
• Subtask 4: 0 / 5