Submission #840681

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
840681	2023-08-31 15:43:57	Lucpp	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	20 ms	432 KiB

longesttrip

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#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;
#define sz(x) (int)(x.size())
mt19937 rng(42);
map<pair<int, int>, bool> cache;
bool qry(int a, int b){
    if(a > b) swap(a, b);
    auto p = make_pair(a, b);
    if(cache.count(p)) return cache[p];
    else return cache[p] = are_connected({a}, {b});
}
vector<int> longest_trip(int N, int D){
    cache.clear();
    (void)D;
    vector<int> ord(N);
    for(int i = 0; i < N; i++) ord[i] = i;
    shuffle(ord.begin(), ord.end(), rng);
    vector<vector<int>> paths{{ord[0]}, {ord[1]}};
    for(int k = 2; k < N; k++){
        int i = ord[k];
        int j = rng() % 2;
        if(rng() % 2){
            if(qry(paths[0].back(), paths[1].back())){
                paths[0].insert(paths[0].end(), paths[1].rbegin(), paths[1].rend());
                paths[1] = {i};
 
 
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• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 60 / 60