Submission #1077082

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077082		MrPavlito	Dreaming (IOI13_dreaming)	C++17	100 / 100	53 ms	15340 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
//#define int long long
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define sc second
#define pii pair<int,int>

using namespace std;

const int MAXN = 1e5+5;
const int mod7 = 1e9+7;
const long long inf = 1e18;
int n;

bool visited[MAXN];
int parents[MAXN];
vector<vector<pii>> graf(MAXN);
vector<long long> dist;
long long mxdist;
long long rez = inf;
long long konacno= 0;

void dfs1(int nod, int p, long long d, int &kraj)
{
    parents[nod] = p;
    visited[nod] = 1;
    if(d>=mxdist)
    {
        kraj = nod;
        mxdist = d;
    }
    for(auto x: graf[nod])if(x.fi!=p)dfs1(x.fi, nod, d+x.sc, kraj);
}

void dfs2(int nod, int p, long long d)
{
    rez = min(rez, max(mxdist -d, d));
    int tr = rez;
    for(auto x: graf[nod])
    {
        if(x.fi == p)continue;
        int p1 = parents[nod];
        if(parents[nod] == x.fi)
        {
            dfs2(x.fi, nod, d+x.sc);
        }
    }

}

void solve(int i)
{
    int nod1 = i;
    mxdist = 0;
    dfs1(i,i,0, nod1);
    int nod2 = i;
    mxdist = 0;
    dfs1(nod1, nod1, 0, nod2);
    rez = inf;
    dfs2(nod2, nod2, 0);
    konacno = max(konacno, mxdist);
    dist.pb(rez);
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    n = N;
    for(int i=0; i<M; i++)
    {
        graf[A[i]].pb(mp(B[i], T[i]));
        graf[B[i]].pb(mp(A[i], T[i]));
    }
    for(int i=0; i<n; i++)if(!visited[i])solve(i);
    sort(all(dist));
    reverse(all(dist));
    //for(auto x: dist)cout << x<< " ";cout << endl;
    if(dist.size() == 1)return konacno;
    konacno = max(konacno,dist[0]+dist[1]+L);
    if(dist.size()>2) konacno = max(konacno,dist[1]+dist[2]+2*L);
    return konacno;
}

Compilation message (stderr)

dreaming.cpp: In function 'void dfs2(int, int, long long int)':
dreaming.cpp:45:13: warning: unused variable 'p1' [-Wunused-variable]
   45 |         int p1 = parents[nod];
      |             ^~
dreaming.cpp:41:9: warning: unused variable 'tr' [-Wunused-variable]
   41 |     int tr = rez;
      |         ^~

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