Submission #49007

#	Time	Username	Problem	Language	Result	Execution time	Memory
49007		Namnamseo	Ball Machine (BOI13_ballmachine)	C++17	77.38 / 100	1086 ms	73028 KiB

ballmachine

#include <bits/stdc++.h>
using namespace std;
#define sz(v) ((int)((v).size()))
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define coord_comp(v) sort(all(v)), v.erase(unique(all(v)), v.end())
#define v_index(v, x) (lower_bound(all(v),x)-(v).begin())
typedef pair<int,int> pp;
typedef long long ll;
void read(int& x){ scanf("%d",&x); }
void read(ll& x){ scanf("%lld",&x); }
template<typename T1,typename T2>
void read(pair<T1,T2>& p){ read(p.first); read(p.second); }
template<typename T,typename... Args>
void read(T&a,Args&...b){ read(a); read(b...); }

int submin[100010];
int insind[100010];
int par[20][100001];

auto comp = [&](const int& a,const int& b){
	return insind[a] < insind[b];
};
set<int,decltype(comp)> s(comp);

vector<int> edge[100010];
int n;

int dfs(int x){
	int ret=x;
	for(int y : edge[x]){
		ret=min(ret, dfs(y));
	}
	return submin[x] = ret;
}

int nowt;
void dd(int x){
	insind[x] = nowt;
	++nowt;
	vector<pp> asdf;
	for(int y : edge[x]){
		asdf.push_back({submin[y], y});
	}
	sort(all(asdf));
	for(pp yy : asdf) dd(yy.second);
}

int cc[100001];

set<int> emptyNodes;

int main(){
	int Q;
	read(n,Q);
	int rt;
	for(int i=1; i<=n; ++i){
		int p; read(p);
		par[0][i]=p;
		if(p==0) rt=i;
		else edge[p].pb(i);
	}
	dfs(rt);
	dd(rt);
	for(int i=1; i<=n; ++i){
		cc[i] = edge[i].size();
		if(cc[i] == 0){
			s.insert(i);
		}
		emptyNodes.insert(i);
	}

	par[0][rt] = -1;
	for(int i=1; i<=17; ++i){
		for(int j=1; j<=n; ++j){
			int t=par[i-1][j];
			if(t == -1) par[i][j]=-1;
			else par[i][j]=par[i-1][t];
		}
	}

	for(;Q--;){
		int q,x;
		read(q,x);
		if(q == 1){
			int p;
			for(;x--;){
				p = *s.begin();
				s.erase(s.begin());
				emptyNodes.erase(p);
				int z=par[0][p];
				if(z != -1){
					--cc[z];
					if(cc[z] == 0){
						s.insert(z);
					}
				}
			}
			printf("%d\n", p);
		} else {
			int step = 0;
			for(int i=17; 0<=i; --i){
				if(par[i][x] == -1) continue;
				int t = par[i][x];
				if(emptyNodes.find(t) == emptyNodes.end())
					x = t,
					step += (1<<i);
			}
			printf("%d\n", step);
			s.insert(x);
			emptyNodes.insert(x);
			if(par[0][x] != -1){
				s.erase(par[0][x]);
				++cc[par[0][x]];
			}
		}
	}

	return 0;
}

Compilation message (stderr)

ballmachine.cpp: In function 'void read(int&)':
ballmachine.cpp:10:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void read(int& x){ scanf("%d",&x); }
                    ~~~~~^~~~~~~~~
ballmachine.cpp: In function 'void read(ll&)':
ballmachine.cpp:11:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void read(ll& x){ scanf("%lld",&x); }
                   ~~~~~^~~~~~~~~~~
ballmachine.cpp: In function 'int main()':
ballmachine.cpp:73:13: warning: 'rt' may be used uninitialized in this function [-Wmaybe-uninitialized]
  par[0][rt] = -1;
  ~~~~~~~~~~~^~~~

• Subtask 1: 25 / 25
• Subtask 2: 19.285714285714285 / 30
• Subtask 3: 31.428571428571427 / 40
• Subtask 4: 1.6666666666666667 / 5