Submission #290134

#	Time	Username	Problem	Language	Result	Execution time	Memory
290134		REALITYNB	Race (IOI11_race)	C++14	9 / 100	3090 ms	15864 KiB

race

#include <bits/stdc++.h> 
#include "race.h"
#define pb push_back
#define intt long long 
#define mp make_pair
#define pii pair<intt,intt> 
#define F first 
#define S second 
using namespace std; 
intt n , k ; 
const intt mxn = 2e5+1 ;
vector<pii> adj[mxn] ; 
vector<intt> sz(mxn) , w(mxn) ,h(mxn) ; 
void sub(intt a , intt p){
    sz[a]=1 ; 
    if(p!=-1) h[a]=h[p]+1 ; 
    for(pii& x : adj[a]){
        if(x.F==p) continue ; 
        w[x.F]=w[a]+x.S ;         
        sub(x.F,a) ; 
        sz[a]+=sz[x.F] ; 
    }
}
intt mn  = 1e9 ; 
vector<intt> p[mxn] ; 
map<intt,multiset<intt>> cnt ; 
void dfs(intt a , intt pp , intt keep){
    intt bigchild = -1 , mx = -1 ; 
    for(pii& y : adj[a]){
        intt x = y.F ; 
        if(x==pp) continue ; 
        if(sz[x]>mx){
            mx=sz[x] ; 
            bigchild= x ; 
        }
    }
    for(pii& y : adj[a]){
        intt x = y.F ; 
        if(x==pp||x==bigchild) continue ; 
        dfs(x,a,0) ; 
    }
    if(bigchild!=-1){
        dfs(bigchild,a,1) ; 
        swap(p[bigchild],p[a]) ;
     //   p[bigchild].swap(p[a]) ; 
    }
    p[a].push_back(a) ; 
    intt target = k+2*w[a] ; 
    if(cnt.count(target-w[a])) mn = min(mn,*(cnt[target-w[a]].begin())-h[a]) ; 
    cnt[w[a]].insert(h[a]) ; 
    for(pii& y : adj[a]){
        if(y.F==pp||y.F==bigchild) continue ; 
        for(intt& x : p[y.F]){
            if(cnt.count(target-w[x])) mn = min(*(cnt[target-w[x]].begin())+h[x]-h[a]*2,mn) ; 
            p[a].pb(x) ; 
        }
        for(intt& x :p[y.F]) cnt[w[a]].insert(h[x]) ; 
    }
    if(keep==0){
        for(intt& x: p[a]){
            cnt[w[x]].erase(cnt[w[x]].find(h[x])) ;
            if(cnt[w[x]].empty()) cnt.erase(cnt.find(w[x])) ;  
        }
    }
}
intt solve(){
    sub(1,-1) ; 
    dfs(1,-1,1) ; 
    if(mn==1e9) return -1; 
    return mn ; 
}
int best_path(int N , int K , int H[][2] , int L[]){
    n = N ; 
    k = K ;
   /* cnt.erase(cnt.begin(),cnt.end()) ; 
    for(intt& x  : h) x = 0 ; 
    for(intt& x : w) x = 0 ; 
    for(vector<intt>& x : p) x.erase(x.begin(),x.end()) ; 
    for(intt i=0;i<=n;i++) cnt[i].erase(cnt[i].begin(),cnt.end()) ; 
    */if(n>100 ) return 0;
    for(intt i=0;i<n;i++){
        adj[H[i][0]].push_back(mp(H[i][1],L[i]));
        adj[H[i][1]].push_back(mp(H[i][0],L[i])) ;  
    }
    return solve() ; 
}

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