Submission #109434

#	Time	Username	Problem	Language	Result	Execution time	Memory
109434		amiratou	Dreaming (IOI13_dreaming)	C++14	14 / 100	62 ms	12020 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
using namespace std;
#define fi first
#define se second
#define INF (int)(1e9)
vector<vector<pair<int,int> > > vec;
bool vis[100005];
int maxi=0,A,idx=0;
vector<pair<int,int> > tree_d;
pair<int,int> p[100005],center[100005];
vector<int> nodes;
void dfs(int node,int d){
	nodes.push_back(node);
	if(d>maxi)
		A=node,maxi=d;
	vis[node]=1;
	for(auto child:vec[node])
		if(child.fi!=p[node].fi){
			vis[child.fi]=1;
			p[child.fi]={node,child.se};
			dfs(child.fi,d+child.se);
		}
}
pair<int,int> findCenter(int node){
	maxi=0;
	dfs(node,0);
	for(auto i:nodes)
		p[i]={-1,-1};
	nodes.clear();
	int B=A,sum=0,mini=INF,c=node,sh=INF;
	maxi=0;
	dfs(B,0);
	nodes.clear();
	for(;A!=-1;sum+=p[A].se,A=p[A].fi){
		if(abs(maxi/2-sum)<mini)
			mini=abs(maxi/2-sum),c=A,sh=sum;
	}
	tree_d.push_back({maxi,idx});
	return {c,max(maxi-sh,0)};
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	vec.resize(N);
	for (int i = 0; i < M; ++i)
	{
		vec[A[i]].push_back({B[i],T[i]});
		vec[B[i]].push_back({A[i],T[i]});
	}
	for (int i = 0; i < N; ++i)
		if(!vis[i])
			center[idx++]=findCenter(i);
	sort(tree_d.begin(),tree_d.end(),greater<pair<int,int> >());
	int centroid=center[0].first,ans=tree_d[0].fi,max_d=0;
	for (int i = 0; i < idx-1; ++i)
	{
		if(center[tree_d[i+1].se].se>center[tree_d[i].se].se)
			centroid=center[tree_d[i+1].se].fi;
		ans=max(ans,center[tree_d[i+1].se].se+center[tree_d[i].se].se+L);
	}
    return ans;
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:53:6: warning: variable 'centroid' set but not used [-Wunused-but-set-variable]
  int centroid=center[0].first,ans=tree_d[0].fi,max_d=0;
      ^~~~~~~~
dreaming.cpp:53:48: warning: unused variable 'max_d' [-Wunused-variable]
  int centroid=center[0].first,ans=tree_d[0].fi,max_d=0;
                                                ^~~~~

• Subtask 1: 14 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23