Submission #998232

#	Time	Username	Problem	Language	Result	Execution time	Memory
998232		MarwenElarbi	Race (IOI11_race)	C++17	0 / 100	6 ms	33372 KiB

race

#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ii pair<int,int>
#define MAX_N 500000
const int nax=2e5+5;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<pair<int,int>> adj[nax];
int sz[nax];
bool removed[nax];
vector<vector<pair<ll,pair<ll,int>>>> dist(nax);
vector<map<int,vector<pair<int,int>>>> mp(nax);
set<int> st[nax];
int get_tree_size(int x,int p){
    sz[x]=1;
    for(auto u:adj[x]){
        if(u.fi==p||removed[u.fi]) continue;
        sz[x]+=get_tree_size(u.fi,x);
    }
    return sz[x];
}
int get_centroid(int x,int t_sz,int p){
    for(auto u:adj[x]){
        if(u.fi==p||removed[u.fi]) continue;
        if(sz[u.fi]*2>t_sz){
            return get_centroid(u.fi,t_sz,x);
        }
    }
    return x;
}
void get_dist(int x,int centroid,int p,pair<ll,int> cur){
    for(auto u:adj[x]){
        if(u.fi==p||removed[u.fi]) continue;
        cur.fi+=u.se;
        cur.se++;
        get_dist(u.fi,centroid,x,cur);
        cur.fi-=u.se;
        cur.se--;
    }
    //cout <<x<<" "<<centroid<<" "<<cur.fi<<" "<<cur.se<<endl;
    mp[centroid][cur.fi].pb({x,cur.se});
    dist[x].pb({centroid,cur});
    st[x].insert(centroid);
}
void build(int x){
    int centroid=get_centroid(x,get_tree_size(x,-1),-1);
    for(auto u:adj[centroid]){
        if(removed[u.fi]) continue;
        get_dist(u.fi,centroid,centroid,make_pair(u.se,1));
    }
    removed[centroid]=true;
    for(auto u:adj[centroid]){
        if(removed[u.fi]) continue;
        build(u.fi);
    }
}
int n,k;
int query(int x){
    int ans=1e9;
    if(mp[x].count(k)){
        for (int i = 0; i < mp[x][k].size(); ++i)
        {
            ans=min(ans,mp[x][k][i].se);
        }
    }
    for(int u=0;u<dist[x].size();u++){
        for (int i = 0; i < (int)mp[dist[x][u].fi][k-dist[x][u].se.fi].size(); ++i)
        {
            if(mp[dist[x][u].fi][k-dist[x][u].se.fi][i].fi==x) continue;
            if(u<dist[x].size()-1&&st[mp[dist[x][u].fi][k-dist[x][u].se.fi][i].fi].count(dist[x][u+1].fi)) continue;
            ans=min(ans,dist[x][u].se.se+mp[dist[x][u].fi][k-dist[x][u].se.fi][i].se);
            //cout <<x<<" "<<dist[x][u].fi<<" "<<mp[dist[x][u].fi][k-dist[x][u].se.fi][i].fi<<" "<<ans<<endl;
        }
    }
    return ans;
}
int best_path(int N, int K, int H[][2], int L[])
{
    n=N;
    k=K;
    for (int i = 0; i < n-1; ++i)
    {
        adj[H[i][0]].pb({H[i][1],L[i]});
        adj[H[i][1]].pb({H[i][0],L[i]});
    }
    build(0);
    int ans=1e9;
    for (int i = 0; i < n; ++i)
    {
        int cur=query(i);
        ans=min(ans,cur);
    }
    if(ans==1e9) return -1;
    else return ans;
}

Compilation message (stderr)

race.cpp: In function 'int query(int)':
race.cpp:67:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |         for (int i = 0; i < mp[x][k].size(); ++i)
      |                         ~~^~~~~~~~~~~~~~~~~
race.cpp:72:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, std::pair<long long int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |     for(int u=0;u<dist[x].size();u++){
      |                 ~^~~~~~~~~~~~~~~
race.cpp:76:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, std::pair<long long int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |             if(u<dist[x].size()-1&&st[mp[dist[x][u].fi][k-dist[x][u].se.fi][i].fi].count(dist[x][u+1].fi)) continue;
      |                ~^~~~~~~~~~~~~~~~~

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