Submission #412497

#	Time	Username	Problem	Language	Result	Execution time	Memory
412497		jeqcho	Race (IOI11_race)	C++17	9 / 100	380 ms	262148 KiB

race

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pair<int,int>> vpi;

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

#define pb push_back
#define rsz resize
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
#define fi first
#define se second

struct triple{
	int a,b,c;
};

int const n=2e5;
int const k_=1e2+1;
triple dp[n][k_];
vpi adj[n];
int const INF=1e9;
int mn=INF;
int k;

void dfs(int now, int par)
{
	F0R(i,k+1)
	{
		dp[now][i]={INF,-1,-1};
	}
	dp[now][0].a=0;
	dp[now][0].b=now;
	trav(chi,adj[now])
	{
		if(chi.fi==par)continue;
		dfs(chi.fi,now);
		F0R(i,k+1)
		{
			if(i-chi.se<0)continue;
			if(dp[chi.fi][i-chi.se].a+1 == dp[now][i].a)
			{
				dp[now][i].c=chi.fi;
			}
			else if(dp[chi.fi][i-chi.se].a+1 < dp[now][i].a)
			{
				dp[now][i] = {dp[chi.fi][i-chi.se].a+1, chi.fi,-1};
			}
		}
	}
	F0R(i,k+1)
	{
		if(dp[now][i].a==-1)continue;
		if(dp[now][k-i].a==-1)continue;
		if(dp[now][i].b==dp[now][k-i].b)
		{
			if(dp[now][i].c==-1&&dp[now][k-i].c==-1)continue;
		}
		mn=min(mn,dp[now][i].a+dp[now][k-i].a);
	}
}

int best_path(int N, int K, int H[][2], int L[]){
	k=K;
	F0R(i,N-1)
	{
		int u = H[i][0];
		int v = H[i][1];
		adj[u].pb({v,L[i]});
		adj[v].pb({u,L[i]});
	}
	dfs(0,-1);
	if(mn>=INF)return -1;
	return mn;
}

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