Submission #99947

#	Time	Username	Problem	Language	Result	Execution time	Memory
99947		TadijaSebez	Fireworks (APIO16_fireworks)	C++11	7 / 100	9 ms	7552 KiB

fireworks

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N=300050;
int par[N],len[N];
ll dep[N],dp[N],sz[N];
vector<int> E[N];
void DFS(int u)
{
	if(E[u].size()==0) return;
	vector<ll> work;
	for(int v:E[u])
	{
		DFS(v);
		dp[u]+=dp[v];
		work.pb(sz[v]+len[v]);
	}
	sort(work.begin(),work.end());
	if(work.size()&1)
	{
		int mid=(work.size()+1)/2;
		sz[u]=work[mid-1];
		for(ll p:work) dp[u]+=abs(sz[u]-p);
	}
	else
	{
		int mid=work.size()/2;
		ll a=0,b=0;
		for(ll p:work) a+=abs(work[mid-1]-p);
		for(ll p:work) b+=abs(work[mid]-p);
		if(a<=b) sz[u]=work[mid-1],dp[u]+=a;
		else sz[u]=work[mid],dp[u]+=b;
	}
	//printf("u:%i dp:%lld sz:%lld\n",u,dp[u],sz[u]);
}
int main()
{
	int n,m;
	scanf("%i %i",&n,&m);
	n+=m;
	for(int i=2;i<=n;i++)
	{
		scanf("%i %i",&par[i],&len[i]);
		dep[i]=dep[par[i]]+len[i];
		E[par[i]].pb(i);
	}
	DFS(1);
	printf("%lld\n",dp[1]);
	return 0;
}

Compilation message (stderr)

fireworks.cpp: In function 'int main()':
fireworks.cpp:40:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i %i",&n,&m);
  ~~~~~^~~~~~~~~~~~~~~
fireworks.cpp:44:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%i %i",&par[i],&len[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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