Submission #320014

#	Time	Username	Problem	Language	Result	Execution time	Memory
320014		neki	Race (IOI11_race)	C++14	0 / 100	4 ms	5100 KiB

race

//#include "race.h"
#include <bits/stdc++.h>
#define loop(i, a, b) for(long long i=a;i<b;i++)
#define pool(i, a, b) for(long long i=a-1;i>=b;i--)
#define fore(i, a) for(auto&& i:a)
#define fi first
#define se second
#define ps(a) push_back(a)
#define pb(a) pop_back(a)
#define sc scanf
#define vc vector
#define pa pair<ll, ll>
#define ll int
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define llmax LLONG_MAX/2
#define llmin -LLONG_MAX/2
using namespace std;
#define mn 201000
#define pa pair<ll, ll>
#define ld long double 
vc<pa> edg[mn]; 
ll n, k, vis[mn], ans=0;
ll fnd(ll st){
    vc<ll> sz(n, 1);
    function<void (ll, ll)> psa=[&](ll u, ll p){
        fore(v, edg[u]) if(!vis[v.fi] and v.fi!=p) psa(v.fi, u), sz[u]+=sz[v.fi];
    };
    psa(st, -1);
    function<ll (ll, ll)> dfs=[&](ll u, ll p){
        fore(v, edg[u]) if(!vis[v.fi] and v.fi!=p and sz[v.fi]>n/2) return dfs(v.fi, u);
        return u;
    };
    return dfs(st, -1);
}

vc<ll> cur;
void getd(ll u, ll p, ll dist){
    cur.ps(dist);
    fore(v, edg[u]) if(!vis[v.fi] and v.fi!=p) getd(v.fi, u, dist+v.se);
}

void dec(ll st){
    ll c=fnd(st);
    
    map<ll, ll> al;al[0]=1;
    fore(v, edg[c]) if(!vis[v.fi]){
        cur.clear();
        getd(v.fi, c, v.se);
        fore(d, cur) if(al.find(k-d)!=al.end()) ans+=al[k-d];
        fore(d, cur) al[d]++;
    }
    
    vis[c]=1;
    fore(v, edg[c]) if(!vis[v.fi]) dec(v.fi);
}
ll best_path(ll N, ll K, ll h[][2], ll l[]){
    n=N, k=K;
    loop(i, 0, n-1){
        edg[h[i][0]].ps(make_pair(h[i][1], l[i]));
        edg[h[i][1]].ps(make_pair(h[i][0], l[i]));
    }
    dec(0);
    return ans;
}

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