Submission #551266

#	Time	Username	Problem	Language	Result	Execution time	Memory
551266		AmShZ	Race (IOI11_race)	C++11	0 / 100	3 ms	4948 KiB

race

//khodaya khodet komak kon
# include "race.h"
# include <bits/stdc++.h>

using namespace std;

typedef long long                                        ll;
typedef long double                                      ld;
typedef pair <int, int>                                  pii;
typedef pair <pii, int>                                  ppi;
typedef pair <int, pii>                                  pip;
typedef pair <pii, pii>                                  ppp;
typedef pair <ll, ll>                                    pll;

# define A                                               first
# define B                                               second
# define endl                                            '\n'
# define sep                                             ' '
# define all(x)                                          x.begin(), x.end()
# define kill(x)                                         return cout << x << endl, 0
# define SZ(x)                                           int(x.size())
# define lc                                              id << 1
# define rc                                              id << 1 | 1
# define fast_io                                         ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);

ll power(ll a, ll b, ll md) {return (!b ? 1 : (b & 1 ? a * power(a * a % md, b / 2, md) % md : power(a * a % md, b / 2, md) % md));}

const int xn = 2e5 + 10;
const int xm = 1e6 + 10;
const int sq = 320;
const int inf = 1e9 + 10;
const ll INF = 1e18 + 10;
const ld eps = 1e-15;
const int mod = 1e9 + 7;//998244353;
const int base = 257;

int sz[xn], ans = inf, a[xm], ptr, k;
pii b[xn];
bool hide[xn];
vector <pii> adj[xn];

void plant(int v, int p = - 1){
	sz[v] = 1;
	for (pii u : adj[v])
		if (u.A != p && !hide[u.A])
			plant(u.A, v), sz[v] += sz[u.A];
}
int find_centroid(int v, int s, int p = - 1){
	for (pii u : adj[v])
		if (u.A != p && !hide[u.A] && s < 2 * sz[u.A])
			return find_centroid(u.A, s, v);
	return v;
}
void DFS(int v, int p = - 1, int h = 0, int dis = 0){
	if (k < dis)
		return;
	if (k == dis)
		ans = min(ans, h);
	else if (a[k - dis])
		ans = min(ans, h + a[k - dis]);
	b[ptr ++] = {dis, h};
	for (pii u : adj[v])
		if (u.A != p && !hide[u.A])
			DFS(u.A, v, h + 1, dis + u.B);
}
void solve(int v){
	plant(v);
	v = find_centroid(v, sz[v]);
	hide[v] = true;
	vector <int> V;
	for (pii u : adj[v]){
		if (hide[u.A])
			continue;
		ptr = 0;
		DFS(u.A, v, 1, u.B);
		for (int i = 0; i < ptr; ++ i){
			if (!a[b[i].A])
				a[b[i].A] = inf;
			a[b[i].A] = min(a[b[i].A], b[i].B);
			V.push_back(b[i].A);
		}
	}
	for (int x : V)
		a[x] = 0;
	for (pii u : adj[v])
		if (!hide[u.A])
			solve(u.A);
}

int best_path(int N, int K, int H[][2], int L[]){
	k = K;
	for (int i = 0; i < N - 1; ++ i){
		int v = H[i][0], u = H[i][1], w = L[i];
		adj[v].push_back({u, w});
		adj[u].push_back({v, w});
	}
	solve(0);
	return ans;
}

/*
int main(){
	fast_io;

	count_routes();

	return 0;
}
*/
/*
5 5 2
1 0
1 2
3 2
1 3
4 2
2
3 1
*/

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