Submission #1056907

#	Time	Username	Problem	Language	Result	Execution time	Memory
1056907		Malix	Thousands Islands (IOI22_islands)	C++17	Compilation error	0 ms	0 KiB

islands

#include "islands.h"

#include <variant>
#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> tii;
typedef vector<ll> li;
typedef vector<li> lii;
 
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define LSOne(s) ((s)&(-s))
 
ll INF=1e18+10;
int inf=1e9+10;
ll M=1e9+7;

int n,m; 
vi ans;
vector<pii> arr;
vi vis;

void bfs(int x){
  return;
}

std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {
  n=N;m=M;
  if(n==2){
    if(m<=2)return false;
    vi a;
    REP(i,0,m)if(U[i]==0)a.PB(i);
    int p=-1;
    REP(i,0,m)if(U[i]!=0)p=i;
    int k=a.size();
    if(k<2||p==-1)return false;
    ans.PB(a[0]);ans.PB(p);ans.PB(a[1]);ans.PB(a[0]);ans.PB(p);ans.PB(a[1]);
    return ans;
  }
  arr.resize(n);
  REP(i,0,m){
    arr[U[i]].PB({V[i],i});
    arr[V[i]].PB({U[i],i});
  }
  if(a[0].size()>=2){
    int x=a[0][0].S;
    int y=a[a[0][0].F][0].S;
    int c=a[0][1].S;
    int d=a[a[0][1].F][0].S;
    ans.PB(x);ans.PB(y);ans.PB(c);ans.PB(d);ans.PB(y);ans.PB(x);ans.PB(d);ans.PB(c);
    return ans;
  }
  vis.resize(n,0);
  bfs(0);
  return false;
}

Compilation message (stderr)

islands.cpp: In function 'std::variant<bool, std::vector<int, std::allocator<int> > > find_journey(int, int, std::vector<int>, std::vector<int>)':
islands.cpp:55:6: error: 'a' was not declared in this scope
   55 |   if(a[0].size()>=2){
      |      ^