Submission #976096

#	Time	Username	Problem	Language	Result	Execution time	Memory
976096		Amaarsaa	Race (IOI11_race)	C++14	0 / 100	3 ms	13916 KiB

race

#include "race.h"
#include<bits/stdc++.h>
using namespace std;
#define MAX_N 500000
 
vector < pair < int, int > > adj[200004];
int sz[200004], used[200005] = {0}, d[1000004];
int N, K;
int H[MAX_N][2];
int L[MAX_N];
vector < int > v;
int find_size(int node, int parent) {
	sz[node] = 1;
	for ( pair <int,int >& A : adj[node]) {
		int child = A.first;
		if ( used[child] || parent == child) continue;
		sz[node] += find_size(child, node);
	}
	return sz[node];
}
int find_centroid(int node, int parent, int n) {
	for ( pair <int, int>& A : adj[node]) {
		int child = A.first;
		if ( child == parent || used[child] ) continue;
		if ( sz[child] * 2 > n) return find_centroid(child, node, n);
		
	}
	return node;
}
int ans = -1;
void dfs(int node, int parent, int budjaagaa, int dist, int depth) {
	if ( dist > K) return;
	if ( budjaagaa) {
		if ( d[dist] == -1) d[dist] = depth;
		else d[dist] = min(d[dist], depth);
		v.push_back(dist);
	}
	else {
		if ( d[K - dist] != -1) {
			if ( ans == -1) ans = depth + d[K - dist];
			else ans = min(ans, depth + d[K - dist]);
		}
	}
	for ( pair < int, int>&A : adj[node]) {
		int child = A.first;
		if ( used[child] || child == parent) continue;
		dfs(child, node, budjaagaa, dist + A.second, depth + 1);
	}
}
void solve(int node) {
	int c = find_centroid(node, node, find_size(node, node));
	used[c] = 1;
	v.clear();
	for ( pair <int, int>& A : adj[c]) {
		int child = A.first;
		if ( used[child]) continue;
		dfs(child, c, 0, A.second, 1);
		dfs(child, c, 1, A.second, 1);
	}
	for (int X : v) {
		d[X] = -1;
	}
	for ( pair <int, int>& A : adj[c]) {
		int child = A.first;
		if ( used[child]) continue;
		solve(child);
	}
}
int best_path(int N, int K, int H[][2], int L[]){
	for (int i = 0; i < (N - 1); i ++) {
		adj[H[i][0]].push_back({H[i][1], L[i]});
		adj[H[i][1]].push_back({H[i][0], L[i]});
	}
	for (int i = 0; i <=K; i ++) d[i] = -1;
	solve(0);
	
	return ans;
}

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