Submission #710448

#	Time	Username	Problem	Language	Result	Execution time	Memory
710448		myrcella	Thousands Islands (IOI22_islands)	C++17	Compilation error	0 ms	0 KiB

islands

//by szh
#include<bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 0x3f
#define rep(i,a,b) for (int i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define ll long long
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
void inc(int &a,int b) {a=(a+b)%mod;}
void dec(int &a,int b) {a=(a-b+mod)%mod;}
int lowbit(int x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}

#include "islands.h"

#include <variant>
#include <vector>

const int maxn = 1010;
int dis[maxn][maxn];
vector <int> pos;
vector <int> cyc;

std::variant<bool, std::vector<int>> find_journey(
    int n, int M, std::vector<int> U, std::vector<int> V) {
  rep(i,0,M) {
    dis[U[i]][V[i]] = 1;
    if (U[i]==0) pos.pb(V[i]);
  }
  rep(k,0,n) rep(i,0,n) rep(j,0,n) {
    dis[i][j]|=(dis[i][k]&dis[k][j]);
  }
  rep(i,0,n) if (dis[i][i]==1) cyc.pb(i);
  vector <int> ret;
  rep(i,0,SZ(pos))
    	rep(j,0,i) 
    		for (int k:cyc) {
              if (dis[pos[i]][k] and dis[pos[j]][k]) return ret;
            }
 return false;
}

int main() {
  int N, M;
  assert(2 == scanf("%d %d", &N, &M));

  std::vector<int> U(M), V(M);
  for (int i = 0; i < M; ++i) {
    assert(2 == scanf("%d %d", &U[i], &V[i]));
  }

  std::variant<bool, std::vector<int>> result = find_journey(N, M, U, V);
  if (result.index() == 0) {
    printf("0\n");
    if (std::get<bool>(result)) {
      printf("1\n");
    } else {
      printf("0\n");
    }
  } else {
    printf("1\n");
    std::vector<int> &canoes = std::get<std::vector<int>>(result);
    printf("%d\n", static_cast<int>(canoes.size()));
    for (int i = 0; i < static_cast<int>(canoes.size()); ++i) {
      if (i > 0) {
        printf(" ");
      }
      printf("%d", canoes[i]);
    }
    printf("\n");
  }
  return 0;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/ccHcethG.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccbyGfPF.o:islands.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status