Submission #717001

#	Time	Username	Problem	Language	Result	Execution time	Memory
717001		HaroldVemeno	Dreaming (IOI13_dreaming)	C++17	18 / 100	45 ms	11112 KiB

dreaming

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

using namespace std;
using ll = long long;

ll rd[100000];
bool vis[100000];
struct W {
    int t;
    int w;
};
vector<vector<W>> al;

void calcrd(int v, int p) {
    vis[v] = true;
    ll mrd = 0;
    for(auto a : al[v]) {
        if(a.t == p) continue;
        calcrd(a.t, v);
        mrd = max(mrd, a.w + rd[a.t]);
    }
    rd[v] = mrd;
}

ll radius(int v, int p, ll tdist) {
    int mrv = -1;
    ll mr = tdist;
    ll mr2 = tdist;
    for(auto a : al[v]) {
        if(a.t == p) continue;
        if(rd[a.t] + a.w >= mr) {
            mrv = a.t;
            mr2 = mr;
            mr = rd[a.t] + a.w;
        } else if(rd[a.t] + a.w >= mr2) {
            mr2 = rd[a.t] + a.w;
        }
    }
    ll br = mr;
    for(auto a : al[v]) {
        if(a.t == p) continue;
        if(a.t == mrv) {
            br = min(br, radius(a.t, v, mr2 + a.w));
        } else {
            br = min(br, radius(a.t, v, mr + a.w));
        }
    }
    return br;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    al.assign(N, {});
    for(int i = 0; i < M; ++i) {
        al[A[i]].push_back({B[i], T[i]});
        al[B[i]].push_back({A[i], T[i]});
    }
    vector<ll> rads;
    for(int i = 0; i < N; ++i) {
        if(vis[i]) continue;
        calcrd(i, -1);
        rads.push_back(radius(i, -1, 0));
    }
    sort(begin(rads), end(rads), greater<ll>{});
    if(rads.size() == 1) return rads[0];
    if(rads.size() == 2) return rads[0] + L + rads[1];
    return max(rads[0] + rads[1] + L, rads[1] + 2*L + rads[2]);
}

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