Submission #728857

#	Time	Username	Problem	Language	Result	Execution time	Memory
728857		Rasoul006	Dreaming (IOI13_dreaming)	C++17	14 / 100	87 ms	37056 KiB

dreaming

#include "dreaming.h"
 
#include <bits/stdc++.h>
 
#define endl "\n"
 
#define F first
 
#define S second
 
#define pb push_back
 
typedef long long ll;
 
using namespace std;
 
const int N = 1e6+5;
 
const long long oo = 1e18 ;
 
vector <pair <ll,ll>> v[N] ;
 
ll n , m , ans , best , mx , dis[N] , dis2[N] ;
 
bool vis[N] ;
 
void dfs (ll u , ll p , ll cost)
{
    dis[u] = cost ;
    vis[u] = true ;
 
    for (auto it : v[u])
    {
        if (it.F != p)
            dfs(it.F , u , cost + it.S);
    }
}
 
bool dfs2 (ll u , ll p , ll cost , ll gol)
{
    bool is = false ;
 
    for (auto it : v[u])
    {
        if (it.F != p)
            is |= dfs2(it.F , u , cost + it.S , gol) ;
    }
 
    is |= (u == gol) ;
    if (is)
        best = min (best , max(cost , mx-cost)) ;
 
    return is ;
}
 
ll p1 , p2 ;
 
ll get (ll p)
{
    mx = 0 ;
    for (int i = 0 ; i<n ; i++)
        dis[i] = 0 ;
 
    dfs(p , p , 0) ;
 
    for (int i = 0 ; i<n ; i++)
    {
        if (dis[i] >= mx)
            p1 = i , mx = dis[i] ;
        dis[i] = 0 ;
    }
 
    mx = 0 ;
    dfs(p1 , p1 , 0) ;
    for (int i = 0 ; i<n ; i++)
    {
        if (dis[i] >= mx)
            p2 = i , mx = dis[i] ;
    }
 
    best = oo ;
    dfs2(p1 , p1 , 0 , p2) ;
    return best ;
}
 
 
int travelTime(int N, int M, int L, int A[], int B[], int T[])
{
    n = N ; m = M ;
 
    ll sum = 0 ;
 
    for (int i = 0 ; i<m ; i++)
    {
        v[B[i]].pb({A[i] , T[i]});
        v[A[i]].pb({B[i] , T[i]});
    }
 
    ans += get(0) ;
 
    ll bans = mx ;
 
    for (int i = 0 ; i<n ; i++)
    {
        if (!vis[i])
        {
            ans += get(i) ;
            break ;
        }
    }
 
    bans = max(bans , mx) ;
 
    return max(bans , ans + L) ;
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:91:8: warning: unused variable 'sum' [-Wunused-variable]
   91 |     ll sum = 0 ;
      |        ^~~

• Subtask 1: 14 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23