#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) begin(a),end(a)
bool connected(deque<int> A, deque<int> B){
vector<int> Av,Bv;Av.clear(),Bv.clear();
for(auto u : A) Av.pb(u);
for(auto u : B) Bv.pb(u);
return are_connected(Av,Bv);
}
vector<int> longest_trip(int N, int D){
vector<int> ord(N,0); iota(all(ord),0);
random_shuffle(all(ord),rng);
deque<int> line1, line2;
line1.push_back(ord[0]);
for(int i = 1; i < N; i++){
int x = ord[i];
if(are_connected({x},{line1.back()})) line1.push_back(x);
else line2.push_back(x);
}
vector<int> ans; ans.clear();
if(line2.empty()){
for(auto u : line1) ans.pb(u);
return ans;
}
if(!connected(line1,line2)){
if(sz(line1)<sz(line2)) swap(line1,line2);
for(auto u : line1) ans.pb(u);
return ans;
}
if(are_connected({line1.back()},{line2.back()})){
for(auto u : line1) ans.pb(u);
reverse(all(line2));
for(auto u : line2) ans.pb(u);
return ans;
}
int l = 0, r = sz(line1)-1;
while(l<r){
int mid = (l+r)/2;
deque<int> dq; dq.clear();
for(int i = 0; i <= mid; i++) dq.pb(line1[i]);
if(connected(dq,line2)) r=mid;
else l=mid+1;
}
int x = l;
l=0, r = sz(line2)-1;
while(l<r){
int mid = (l+r)/2;
vector<int> v; v.clear();
for(int i = 0; i <= mid; i++) v.pb(line2[i]);
if(are_connected({line1[x]},v)) r=mid;
else l=mid+1;
}
int y = l;
for(int i = x-1; i>=0; i--) ans.pb(line1[i]);
for(int i = sz(line1)-1; i>=x; i--) ans.pb(line1[i]);
for(int i = y; i < sz(line2); i++) ans.pb(line2[i]);
for(int i = 0; i < y; i++) ans.pb(line2[i]);
return ans;
}
Compilation message
longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:17:26: error: 'rng' was not declared in this scope
17 | random_shuffle(all(ord),rng);
| ^~~
