Submission #133101

#	Time	Username	Problem	Language	Result	Execution time	Memory
133101		baluteshih	Race (IOI11_race)	C++14	100 / 100	600 ms	42400 KiB

race

#pragma GCC optimize("Ofast","unroll-loops")
#include "race.h"
#include <bits/stdc++.h>
#define jizz ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define pb push_back
#define ET cout << "\n"
#define MEM(i,j) memset(i,j,sizeof i)
#define F first
#define S second
#define MP make_pair
#define ALL(v) v.begin(),v.end()
#define DB(a,s,e) {for(int i=s;i<e;++i) cout << a[i] << " ";ET;}
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
bitset<200005> vis;
vector<pii> G[200005];
const int INF=1e9;
int ans=INF,k,wei,w[200005],tmp[1000005];
 
void center(int u,int f,int &cent,int sz)
{
	int x=0;
	w[u]=1;
	for(pii i:G[u])
		if(i.F!=f&&!vis[i.F])
			center(i.F,u,cent,sz),x=max(x,w[i.F]),w[u]+=w[i.F];
	x=max(x,sz-w[u]);
	if(x<wei) wei=x,cent=u;
}
 
void dfs(int u,int f,int d,int r,vector<pii> &v)
{
	v.pb(MP(d,r));
	for(pii i:G[u])
		if(i.F!=f&&!vis[i.F])
			dfs(i.F,u,d+i.S,r+1,v);
}
 
void cut(int u,int sz)
{
	int c;
	wei=INF,center(u,u,c,sz);
	vis[c]=1;
	for(pii i:G[c])
		if(!vis[i.F])
			if(w[i.F]>w[c]) cut(u,w[u]-w[c]);
			else cut(i.F,w[i.F]);
	vector<int> rv;
	for(pii i:G[c])
		if(!vis[i.F])
		{
			vector<pii> v;
			dfs(i.F,i.F,i.S,1,v);
			for(pii j:v)
				if(j.F<=k&&tmp[k-j.F]!=INF)
					ans=min(ans,j.S+tmp[k-j.F]);
			for(pii j:v)
				if(j.F<=k) 
					if(tmp[j.F]==INF) tmp[j.F]=j.S,rv.pb(j.F);
					else tmp[j.F]=min(tmp[j.F],j.S);
		}
	for(int i:rv)
		tmp[i]=INF;
	vis[c]=0;
}
 
 
int best_path(int N, int K, int H[][2], int L[])
{
	k=K,tmp[0]=0;
	for(int i=1;i<=K;++i)
		tmp[i]=INF;
	for(int i=0;i<N-1;++i)
		G[H[i][0]].pb(MP(H[i][1],L[i])),G[H[i][1]].pb(MP(H[i][0],L[i]));
	cut(0,N);
	if(ans==INF) return -1;
	return ans;
}

Compilation message (stderr)

race.cpp: In function 'void cut(int, int)':
race.cpp:48:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   if(!vis[i.F])
     ^
race.cpp:61:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
     if(j.F<=k) 
       ^

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