Submission #1311080

#	Time	Username	Problem	Language	Result	Execution time	Memory
1311080		hitsuuj	Race (IOI11_race)	C++20	43 / 100	351 ms	84636 KiB

race

#include "race.h"
#include <bits/stdc++.h>
using namespace std; 
#define pii pair<int,int> 
#define pb push_back
#define ll long long
#define inf 1e18
const int lim=2e5;
vector<pii>g[lim+10];
ll dis[lim+10]; 
vector<int>l(lim+10);
ll ans=inf,n,k; 
// somehow semakin besar knya bakalan salah 
map<ll,ll> dfs(int u,int par,int dep){
    map<ll,ll>cur;
    cur[dis[u]]=dep;
    for(auto [v,w]:g[u]){
        if(v==par) continue; 
        dis[v]=dis[u]+w;
        map<ll,ll> anak=dfs(v,u,dep+1);
        if(anak.size()>cur.size()){ 
            swap(cur,anak);
        }
        // cout<<u<<' '<<v<<endl; 
        for(auto [x,y]:anak){
            ll tar=k-x+2*dis[u];
            // if(tar<0) continue; 
            if(cur.count(tar)){
                ans=min(ans,cur[tar]+y-2*dep);
            }
            if(cur.count(x)) cur[x]=min(cur[x],y);
            else cur[x]=y;
        }
        for(auto [x,y]:anak){
            if(cur.count(x)) cur[x]=min(cur[x],y);
            else cur[x]=y;
        }
    }
    return cur; 
}
int best_path(int N, int K, int H[][2], int L[])
{
  ans=inf;
    n=N,k=K;
    for(int i=0;i<n-1;i++){
        g[H[i][0]].pb({H[i][1],L[i]}); 
        g[H[i][1]].pb({H[i][0],L[i]}); 
    }
    
    dfs(0,-1,0);
    for(int i=0;i<n-1;i++){
        g[H[i][0]].clear();
        g[H[i][1]].clear();
    }
    if(ans==inf) return -1;
    return ans;

}

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