제출 #488623

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
488623		ssense	경주 (Race) (IOI11_race)	C++14	0 / 100	1 ms	204 KiB

race

#include <bits/stdc++.h>
#include "race.h"
#define startt ios_base::sync_with_stdio(false);cin.tie(0);
typedef long long  ll;
using namespace std;
#define vint vector<int>
#define all(v) v.begin(), v.end()
#define MOD 1000000007
#define MOD2 998244353
#define MX 1000000000
#define MXL 1000000000000000000
#define PI (ld)2*acos(0.0)
#define nax 200005
#define pb push_back
#define sc second
#define fr first
//#define int long long
//#define endl '\n'
#define ld long double
#define NO cout << "NO" << endl
#define YES cout << "YES" << endl
																															int ceildiv(int one, int two) {if (one % two == 0) {return one / two;}else {return one / two + 1;}} int power(int n, int pow, int m) {if (pow == 0) return 1;if (pow % 2 == 0) {ll x = power(n, pow / 2, m);return (x * x) % m;}else return (power(n, pow - 1, m) * n) % m;} int gcd(int a, int b) { if (!b)return a; return gcd(b, a % b);} int factorial(int n, int mod) {if (n > 1)return (n * factorial(n - 1, mod)) % mod; else return 1;} int lcm(int a, int b) {return (a * b) / gcd(a, b);} vector<int> read(int n) {vector<int> a; for (int i = 0; i < n; i++) { int x; cin >> x; a.pb(x);} return a;}//ssense
vector<vector<pair<int, int>>> adj;
int n_glob;
int k_glob;
vint size_sub;
vint del;

int calc(int u, int par)
{
	int children = 1;
	for(auto v : adj[u])
	{
		if(del[v.fr] == 0 && (par == -1 || v.fr != par))
		{
			children+=calc(v.fr, u);
		}
	}
	size_sub[u] = children;
	return children;
}
 
int find_centroid(int u, int size, int par)
{
	for(auto v : adj[u])
	{
		if(v.fr != par && del[v.fr] == 0 && size_sub[v.fr] > size)
		{
			return find_centroid(v.fr, size, u);
		}
	}
	return u;
}
 
int ans = MX;

void assign(int u)
{
	calc(u, -1);
	int centroid = find_centroid(u, size_sub[u] / 2, -1);
	map<int, int> cnt;
	cnt[0] = 0;
	del[centroid] = 1;
	for(auto x : adj[centroid])
	{
		if(del[x.fr] == 1)
		{
			continue;
		}
		map<int, int> now;
		queue<pair<pair<int, int>, pair<int, int>>> q;
		q.push({{x.fr, centroid}, {x.sc, 1}});
		while(!q.empty())
		{
			int node = q.front().fr.fr;
			int parent = q.front().fr.sc;
			int length = q.front().sc.fr;
			int highways = q.front().sc.sc;
			if(now[length] == 0)
			{
				//lucreaza din cauza ca bfs.
				now[length] = highways;
			}
			q.pop();
			for(auto y : adj[node])
			{
				if(del[y.fr] == 0 && y.fr != parent)
				{
					q.push({{y.fr, node}, {length+y.sc, highways+1}});
				}
			}
		}
		for(auto num : now)
		{
			if(k_glob == num.fr)
			{
				ans = min(ans, num.sc);
			}
			if(k_glob > num.fr && cnt[k_glob-num.fr] != 0)
			{
				ans = min(ans, num.sc+cnt[k_glob-num.fr]);
			}
		}
		for(auto num : now)
		{
			if(cnt[num.fr] == 0)
			{
				cnt[num.fr] = num.sc;
			}
			else
			{
				cnt[num.fr] = min(cnt[num.fr], num.sc);
			}
		}
	}
	for(auto x : adj[u])
	{
		if(del[x.fr] == 0)
		{
			assign(x.fr);
		}
	}
}

int best_path(int n, int k, int h[][2],int l[])
{
	n_glob = n;
	k_glob = k;
	for(int i = 0; i <= n; i++)
	{
		vector<pair<int, int>> cop;
		adj.pb(cop);
	}
	for(int i = 0; i < n-1; i++)
	{
		adj[h[i][0]].pb({h[i][1], l[i]});
		adj[h[i][1]].pb({h[i][0], l[i]});
	}
	size_sub = vint(n+1);
	del = vint(n+1);
	assign(0);
	if(ans == MX)
	{
		return -1;
	}
	return ans;
}
/*
int32_t main(){
	startt
	int n, k;
	cin >> n >> k;
	int h[n-1][2], l[n-1];
	for(int i = 0; i < n-1; i++)
	{
		cin >> h[i][0] >> h[i][1];
	}
	for(int i = 0; i < n-1; i++)
	{
		cin >> l[i];
	}
	cout << best_path(n, k, h, l) << endl;
}
 */
/*
3 3
0 1
0 2
1 1
 
4 3
0 1
1 2
1 3
1 2 4
 
11 12
0 1
0 2
2 3
3 4
4 5
0 6
6 7
6 8
8 9
8 10
3 4 5 4 6 3 2 5 6 7
 */

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57