Submission #1263441

#	Time	Username	Problem	Language	Result	Execution time	Memory
1263441		tkhoi13	Dreaming (IOI13_dreaming)	C++20	47 / 100	46 ms	14408 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
using namespace std;

#define REP(i, n) for (int i = 0, _b = (n); i < _b; i++)
#define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; i++)
#define pb push_back
#define szx(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

#define pii pair<int, int>
#define ll long long

const int MAXN = 100000;

vector<pii> adj[MAXN];
vector<ll> dis(MAXN, -1);

ll ans = 0;
ll mx = 0, d = 0;
int par[MAXN];

void dfs(int u, int p = -1) {
    if (mx < dis[u]) mx = dis[u], d = u;
    par[u] = p;

    for (auto& [v, w] : adj[u]) {
        if (v != p) {
            dis[v] = dis[u] + w;
            dfs(v, u);
        }
    }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    REP(i, M) {
        adj[A[i]].pb({B[i], T[i]});
        adj[B[i]].pb({A[i], T[i]});
    }

    vector<ll> half;

    REP(i, N) if (dis[i] == -1) {
        mx = -1;
        d = 0;
        dis[i] = 0;
        dfs(i);
        int d1 = d;

        mx = -1, d = 0;
        dis[d1] = 0;
        dfs(d1);
        int d2 = d;

        ans = max(ans, mx);
        ll ans1 = LLONG_MAX;

        for (int u = d2; u != -1; u = par[u])
            ans1 = min(max(dis[u], mx - dis[u]), ans1);

        half.pb(ans1);
    }

    sort(all(half), greater<ll>());

    if (szx(half) >= 2) {
        ans = max(ans, half[0] + L + half[1]);
    }

    for (int i = 2; i < szx(half); i++) {
        ans = max(ans, half[0] + 1LL * i * L + half[i]);
    }

    return ans;
}

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