Submission #426634

#	Time	Username	Problem	Language	Result	Execution time	Memory
426634		KalasLavas	Traffic (IOI10_traffic)	C++14	100 / 100	1679 ms	194168 KiB

traffic

#include <bits/stdc++.h>
#include "traffic.h"
using namespace std;

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//#undef LOCALKL
#define IO \
ios_base::sync_with_stdio(0);(cin).tie(0);(cout).tie(0)
#define y1 y1_
#define prev prev_
#define all(a) (a).begin(),(a).end()
#define pb push_back
#define eb emplace_back
#define F first
#define S second
#ifdef LOCALKL
// #define cerr cerr<<"\33[1;32m"
// #define cout cout<<"\33[0m"
#else
#ifndef OO
#define endl '\n'
#define cerr if(1){}else cerr
#endif
#endif
#define OK cout<<"OK\n"<<endl;
#define setpre(k) fixed<<setprecision(k)
#define mmset(k,y) memset(k,y,sizeof(k))
#define sz(x) ((int)(x).size())
using pii = pair<int,int>;
using pll = pair<long long,long long>;
using ull = unsigned long long;
using intt = long long;
using ll = long long;
using ld = long double;

const ll m9 = 998244353;
const ll m7 = 1000000007;
const ll m18 = 1000000000000000000;
const ll i127 = 2139062143;
const ll l127 = 9187201950435737471;
vector<int>g[1000001];
int *a;
pll p[1000001];

pll ans = {LLONG_MAX, 0};

pll dfs(int v, int parent)
{
	ll sum=0, res=0;
	for(int u : g[v])
		if(u!=parent)
		{
			pll x = dfs(u, v);
			sum+=x.F;
			res+=x.S;
		}
	p[v]={sum, sum+res};
	// cerr<<v<<'-'<<p[v].F<<'-'<<p[v].S<<endl;
	return {sum+a[v], sum+res};
}
// {sum, res}
void dfs2(int v, int parent, pll up)
{
	// ll sum=0, res=0;
	// cerr<<v<<' '<<up.F<<' '<<up.S<<endl;
	for(int u : g[v])
		if(u!=parent)
		{
			dfs2(u, v, {up.F+p[v].F-p[u].F+a[v]-a[u], (up.F+p[v].F-p[u].F+a[v]-a[u])+(up.S+p[v].S-(p[u].S+p[u].F+a[u]))});
		}
	ans=min(ans, {up.S+p[v].S, v});
}
// 2 1 3 3 0
int LocateCentre(int n, int pp[], int S[], int D[])
{
	a=pp;
	for(int i=0;i<n-1;i++)
	{
		g[S[i]].emplace_back(D[i]);
		g[D[i]].emplace_back(S[i]);
	}
	dfs(0, -1);
	dfs2(0, -1, {0,0});
	cerr<<"> "<<ans.F<<endl;
	return ans.S;
}

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25