Submission #1087178

#	Time	Username	Problem	Language	Result	Execution time	Memory
1087178		MateiKing80	Dreaming (IOI13_dreaming)	C++14	100 / 100	57 ms	19416 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>

using namespace std;

using pii = pair<int, int>;

#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fr first
#define sc second

//using ll = long long;
//#define int ll

vector<int> a, b, t, dp;
vector<vector<pii>> vec;
vector<bool> f;

int dfs1(int nod, int papa)
{
    f[nod] = true;
    int doi = 0, diam = 0;
    for(auto i : vec[nod])
        if(i.fr != papa)
        {
            diam = max(diam, dfs1(i.fr, nod));
            if(dp[nod] <= i.sc + dp[i.fr])
                doi = dp[nod], dp[nod] = i.sc + dp[i.fr];
            else
                doi = max(doi, i.sc + dp[i.fr]);
        }
    return max(diam, dp[nod] + doi);
}

int dfs2(int nod, int papa, int desus = 0)
{
    int ans = desus, doi = 0;
    for(auto i : vec[nod])
        if(i.fr != papa)
        {
            if(ans <= i.sc + dp[i.fr])
                doi = ans, ans = i.sc + dp[i.fr];
            else
                doi = max(doi, i.sc + dp[i.fr]);
        }
    int rasp = ans;
    for(auto i : vec[nod])
        if(i.fr != papa)
        {
            if(ans == i.sc + dp[i.fr])
                rasp = min(rasp, dfs2(i.fr, nod, doi + i.sc));
            else
                rasp = min(rasp, dfs2(i.fr, nod, ans + i.sc));
        }
    return rasp;
}

int travelTime(int n, int m, int l, int A[], int B[], int T[])
{
    vec.resize(n);
    for(int i = 0; i < m; i ++)
        a.pb(A[i]);
    for(int i = 0; i < m; i ++)
        b.pb(B[i]);
    for(int i = 0; i < m; i ++)
        t.pb(T[i]);
    for(int i = 0; i < m; i ++)
        vec[a[i]].pb({b[i], t[i]}), vec[b[i]].pb({a[i], t[i]});
    f.resize(n, false);
    dp.resize(n, 0);
    vector<int> vals, diams;
    for(int i = 0; i < n; i ++)
        if(!f[i])
            diams.pb(dfs1(i, -1)), vals.pb(dfs2(i, -1));
    sort(all(vals), [&](int a, int b){return a > b;});
    sort(all(diams), [&](int a, int b){return a > b;});
    int ans = 0;
    if(vals.size() >= 2)
        ans = vals[0] + vals[1] + l;
    if(vals.size() >= 3)
        ans = max(ans, vals[1] + vals[2] + 2 * l);
    ans = max(ans, diams[0]);
    return ans;
}
/*
int main()
{
    int N, M, L, A[5000], B[5000], T[5000];
    cin >> N >> M >> L;
    for(int i = 0; i < M; i ++)
        cin >> A[i];
    for(int i = 0; i < M; i ++)
        cin >> B[i];
    for(int i = 0; i < M; i ++)
        cin >> T[i];
    cout << travelTime(N, M, L, A, B, T);
}
*/

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