Submission #125654

#	Time	Username	Problem	Language	Result	Execution time	Memory
125654		nxteru	Dreaming (IOI13_dreaming)	C++14	100 / 100	120 ms	21896 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> P;
#define PB push_back
#define F first
#define S second
#define INF 1000000001
int n,m,dp[100005],dp2[100005],ans;
vector<P>g[100005];
bool vis[100005];
int dfs1(int v,int p){
	vis[v]=true;
	int res=0;
	dp[v]=0;
	dp2[v]=0;
	for(int i=0;i<g[v].size();i++){
		int u=g[v][i].F,c=g[v][i].S;
		if(u==p)continue;
		res=max(res,dfs1(u,v));
		int x=dp[u]+c;
		if(dp[v]<x)swap(x,dp[v]);
		dp2[v]=max(dp2[v],x);
	}
	return max(res,dp[v]+dp2[v]);
}
int dfs2(int v,int p,int x){
	int l[g[v].size()],r[g[v].size()];
	for(int i=0;i<g[v].size();i++)l[i]=0,r[i]=0;
	for(int i=0;i<g[v].size();i++){
		int u=g[v][i].F,c=g[v][i].S;
		if(u==p){
			dp[v]=max(dp[v],x+c);
			l[i]=x+c,r[i]=x+c;
		}else l[i]=dp[u]+c,r[i]=dp[u]+c;
	}
	int res=dp[v];
	for(int i=1;i<g[v].size();i++)l[i]=max(l[i],l[i-1]);
	for(int i=g[v].size()-1;i>0;i--)r[i-1]=max(r[i-1],r[i]);
	for(int i=0;i<g[v].size();i++){
		int u=g[v][i].F;
		if(u==p)continue;
		int c=0;
		if(i>0)c=max(c,l[i-1]);
		if(i+1<g[v].size())c=max(c,r[i+1]);
		res=min(res,dfs2(u,v,c));
	}
	return res;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	n=N,m=M;
	for(int i=0;i<m;i++){
		g[A[i]].PB(P(B[i],T[i]));
		g[B[i]].PB(P(A[i],T[i]));
	}
	vector<int>p;
	for(int i=0;i<n;i++){
		if(!vis[i]){
			ans=max(ans,dfs1(i,-1));
			p.PB(dfs2(i,-1,0));
		}
	}
	sort(p.begin(),p.end(),greater<int>());
	for(int i=1;i<p.size();i++)p[i]+=L;
	p.PB(0);
	sort(p.begin(),p.end(),greater<int>());
	return max(ans,p[0]+p[1]);
}

Compilation message (stderr)

dreaming.cpp: In function 'int dfs1(int, int)':
dreaming.cpp:17:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[v].size();i++){
              ~^~~~~~~~~~~~
dreaming.cpp: In function 'int dfs2(int, int, int)':
dreaming.cpp:29:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[v].size();i++)l[i]=0,r[i]=0;
              ~^~~~~~~~~~~~
dreaming.cpp:30:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[v].size();i++){
              ~^~~~~~~~~~~~
dreaming.cpp:38:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<g[v].size();i++)l[i]=max(l[i],l[i-1]);
              ~^~~~~~~~~~~~
dreaming.cpp:40:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[v].size();i++){
              ~^~~~~~~~~~~~
dreaming.cpp:45:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(i+1<g[v].size())c=max(c,r[i+1]);
      ~~~^~~~~~~~~~~~
dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:64:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<p.size();i++)p[i]+=L;
              ~^~~~~~~~~

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