#include"longesttrip.h"
#include<iostream>
using namespace std;
int n;
pair<int,int>find_conn(vector<int>v1,vector<int>v2){
for(int i:v1){
if(are_connected({i},v2)){
for(int j:v2){
if(are_connected({i},{j}))
return{i,j};
}
}
}
// impossible
exit(1);
}
vector<int>merge(vector<int>v1,vector<int>v2){
while(v2.size()){
v1.push_back(v2.back());
v2.pop_back();
}
return v1;
}
pair<vector<int>,vector<int>>merge(vector<int>v1,vector<int>v2,vector<int>v3){
if(are_connected({v1.back()},{v2.back()}))
return{merge(v1,v2),v3};
if(are_connected({v2.back()},{v3.back()}))
return{merge(v2,v3),v1};
return{merge(v1,v3),v2};
}
vector<int>cyclic_shift(vector<int>arr,int a){
// it ends with a
vector<int>res;
bool b1=false;
for(int i:arr){
if(b1)
res.push_back(i);
if(i==a)
b1=true;
}
bool b2=true;
for(int i:arr){
if(i==a)
b2=false;
if(b2)
res.push_back(i);
}
return res;
}
vector<int>longest_trip(int N,int D){
n=N;
vector<vector<int>>arr;
for(int i=0;i<n;i++)
arr.push_back({i});
while(arr.size()>2){
vector<int>v1,v2,v3;
v1=arr.back();
arr.pop_back();
v2=arr.back();
arr.pop_back();
v3=arr.back();
arr.pop_back();
auto res=merge(v1,v2,v3);
arr.push_back(res.first);
arr.push_back(res.second);
}
vector<int>res1=arr[0];
vector<int>res2=arr[1];
if(!are_connected(res1,res2)){
if(res1.size()>res2.size())
return res1;
else
return res2;
}
if(are_connected({res1.back()},{res2.back()}))
return merge(res1,res2);
reverse(res1.begin(),res1.end());
if(are_connected({res1.back()},{res2.back()}))
return merge(res1,res2);
reverse(res2.begin(),res2.end());
if(are_connected({res1.back()},{res2.back()}))
return merge(res1,res2);
reverse(res1.begin(),res1.end());
if(are_connected({res1.back()},{res2.back()}))
return merge(res1,res2);
// both must be cyclical then
auto pr=find_conn(res1,res2);
vector<int>r1=cyclic_shift(res1,pr.first);
vector<int>r2=cyclic_shift(res2,pr.second);
return merge(r1,r2);
}
Compilation message
longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:90:5: error: 'reverse' was not declared in this scope
90 | reverse(res1.begin(),res1.end());
| ^~~~~~~
