Submission #1092457

#	Time	Username	Problem	Language	Result	Execution time	Memory
1092457		alexander707070	Fireworks (APIO16_fireworks)	C++14	0 / 100	3 ms	7772 KiB

fireworks

#include<bits/stdc++.h>
#define MAXN 300007
using namespace std;

const long long inf=1e17;

int n,m;
int p[MAXN],c[MAXN];
vector< pair<int,long long> > v[MAXN];
vector<long long> dists;

long long sum[MAXN],sz[MAXN],ans;

void dfs(int x,long long d){
	sz[x]=(v[x].empty());

	if(sz[x]==1)dists.push_back(d);

	for(int i=0;i<v[x].size();i++){
		dfs(v[x][i].first,d+v[x][i].second);

		sz[x]+=sz[v[x][i].first];
		sum[x]+=sum[v[x][i].first]+v[x][i].second*sz[v[x][i].first];
	}
}

long long solve(int x,long long len,long long e){
	long long res=0;
	long long diff=sum[x]+sz[x]*e-sz[x]*len;
	
	if(diff<-sz[x]/2){
		res+=-(diff+sz[x]/2)/sz[x]+((diff+sz[x]/2)%sz[x]!=0);
		e+=-(diff+sz[x]/2)/sz[x]+((diff+sz[x]/2)%sz[x]!=0);
	}

	if(diff>sz[x]/2){
		res+=min(e,(diff-sz[x]/2)/sz[x]+((diff-sz[x]/2)%sz[x]!=0));
		e-=min(e,(diff-sz[x]/2)/sz[x]+((diff-sz[x]/2)%sz[x]!=0));
	}

	for(int i=0;i<v[x].size();i++){
		res+=solve(v[x][i].first,len-e,v[x][i].second);
	}

	return res;
}

int main(){

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin>>n>>m;
	n+=m;
	for(int i=2;i<=n;i++){
		cin>>p[i]>>c[i];
		v[p[i]].push_back({i,c[i]});
	}

	dfs(1,0);

	ans=inf;
	for(long long len=0;len<=300;len++){

		long long curr=0;
		for(int i=0;i<v[1].size();i++){
			curr+=solve(v[1][i].first,len,v[1][i].second);
		}
		
		ans=min(ans,curr);
	}

	cout<<ans<<"\n";

    return 0;
}

Compilation message (stderr)

fireworks.cpp: In function 'void dfs(int, long long int)':
fireworks.cpp:19:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |  for(int i=0;i<v[x].size();i++){
      |              ~^~~~~~~~~~~~
fireworks.cpp: In function 'long long int solve(int, long long int, long long int)':
fireworks.cpp:41:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |  for(int i=0;i<v[x].size();i++){
      |              ~^~~~~~~~~~~~
fireworks.cpp: In function 'int main()':
fireworks.cpp:67:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |   for(int i=0;i<v[1].size();i++){
      |               ~^~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 19
• Subtask 3: 0 / 29
• Subtask 4: 0 / 45