Submission #1092443

#	Time	Username	Problem	Language	Result	Execution time	Memory
1092443		alexander707070	Fireworks (APIO16_fireworks)	C++14	0 / 100	989 ms	2780 KiB

fireworks

#include<bits/stdc++.h>
#define MAXN 100007
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;
	
	while(diff<-sz[x]/2){diff+=sz[x]; e++; res++;}
	while(diff>sz[x]/2 and e>0){diff-=sz[x]; e--; res++;}

	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(){
	
	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:dists){
		ans=min(ans,solve(2,len,v[1][0].second));
	}

	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:34:15: 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]
   34 |  for(int i=0;i<v[x].size();i++){
      |              ~^~~~~~~~~~~~

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