Submission #411342

#	Time	Username	Problem	Language	Result	Execution time	Memory
411342		Mahmudul_Kabir	Race (IOI11_race)	C++14	0 / 100	2 ms	332 KiB

race

#include "race.h"

#include "iostream"
#include "algorithm"
#include "iomanip"
#include "vector"
#include "set"
#include "sstream"
#include "fstream"
#include "cstring"
#include "stack"
#include "cmath"
#include "utility"
#include "map"
#include "bitset"
#include "cassert"
#include "deque"

#define sp <<" "
#define el <<"\n"
#define S second
#define F first
#define all(ar) ar.begin(),ar.end()
#define pb push_back
#define pii pair<ll,ll> 
#define vvp vector<vector<pii>> 

using namespace std;
using ll = long long;

const ll mod = 1000000007;
const ll si = 200005;

vvp g;
ll n,mxc,cnt[si],ans = mod,k;
bitset<si> ded;

int H[si][2],L[si],N,K;

void dfs(ll v,ll p,vector<ll> &sz){
	sz[v] = 1;
	for(pii r: g[v]){
		if(r.F == p || ded[r.F]) continue;
		dfs(r.F,v,sz);
		sz[v] += sz[r.F];
	}
	return;
}

ll f_cen(ll v,ll p,ll lim,vector<ll> &sz){
	for(pii r: g[v]){
		if(r.F ==p || ded[r.F]) continue;
		if(sz[r.F] > lim) return f_cen(r.F,v,lim,sz);
	}
	return v;
}

void count(ll v,ll p,ll cost,ll dep,bool ad){
	if(cost > k) return;
	mxc = max(cost,mxc);
	if(ad) cnt[cost] = min(cnt[cost],dep);
	else ans = min(ans,dep + cnt[k - cost]);
	for(pii r: g[v]){
		if(r.F == p || ded[r.F]) continue;
		count(r.F,v,cost + r.S,dep+1,ad);
	}
	return;
}

void dec(ll v){
	static vector<ll> sz(n+1);
	dfs(v,0,sz);
	ll lim = (sz[v]/2);
	ll cen = f_cen(v,0,lim,sz);
	mxc = 0;
	cnt[0] = 0;
	ded[cen] = 1;
	for(pii r: g[cen]){
		if(ded[r.F]) continue;
		count(r.F,cen,r.S,1,0);
		count(r.F,cen,r.S,1,1);
	}
	for(ll i = 0; i <= mxc; i++) cnt[i] = mod;
	for(pii r: g[cen]){
		if(ded[r.F]) continue;
		dec(r.F);
	}
	return;
}


int best_path(int N, int K, int H[][2], int L[])
{ 
	n = N;
	k = K;
	g.assign(n+1,{});
	for(int i = 0; i < n - 1; i++){
		int a = H[i][0], b = H[i][1], c = L[i];
		g[a].pb({b,c});
		g[b].pb({a,c});
	}
	fill(cnt,cnt+n,mod);
	dec(0);
	return (ans == mod? -1 : ans);
}

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