Hämähäkit

#include <iostream>
#include <complex>
#include <vector>
#include <algorithm>
using namespace std;
typedef complex<double> V;

const int MN = 1<<18;
V vs[MN];


vector<int> es[MN];
int to[MN];
int tidx[MN];
bool done[MN];
bool isEnd[MN];

bool dfs(int n, int f) {
	done[n]=1;
//	cout<<"dfs "<<f<<" -> "<<n<<'\n';
	if (isEnd[n]) return 1;
	int st=0;
	if (f>=0) {
		while(to[es[n][st]] != f) ++st;
	}
	int s=es[n].size();
	for(int i=0; i<s; ++i) {
		int e=es[n][(st+i)%s];
		int t=to[e];
		if (done[t]) continue;
//		done[e]=done[e^1]=1;
		if (dfs(t, n)) {
			return 1;
		}
	}
//	cout<<"return "<<f<<" <- "<<n<<'\n';
	return 0;
}

V curV;
double ang(int x) {
	V v = vs[to[x]] - curV;
	return -atan2(v.real(), v.imag());
}
bool cmp(int a, int b) {
	return ang(a) < ang(b);
}

bool cmpy(int a, int b) {
	return vs[a].imag() < vs[b].imag();
}

int main() {
	int n,m,w;
	cin>>n>>m>>w;
	vector<int> starts;
	for(int i=0; i<n; ++i) {
		int x,y;
		cin>>x>>y;
		vs[i] = V(x,y);
		isEnd[i] = x==w;
		if (x==0) {
			starts.push_back(i);
		}
	}
	for(int i=0; i<m; ++i) {
		int a,b;
		cin>>a>>b;
		--a,--b;
		to[2*i]=b;
		to[2*i+1]=a;
		es[a].push_back(2*i);
		es[b].push_back(2*i+1);
	}
	for(int i=0; i<n; ++i) {
		curV = vs[i];
		sort(es[i].begin(), es[i].end(), cmp);
//		cout<<i<<' '<<curV<<": ";for(int x: es[i]) cout<<to[x]<<' ';cout<<'\n';
	}

	sort(starts.begin(), starts.end(), cmpy);
	int res=0;
	for(int v: starts) {
//		cout<<"start "<<v<<'\n';
		if (dfs(v, -1)) {
//			cout<<"found\n";
			++res;
		}
	}
	cout<<res<<'\n';
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 1

Verdict: ACCEPTED

Test 7

Group: 1

Verdict: ACCEPTED

Test 8

Group: 1

Verdict: ACCEPTED

Test 9

Group: 1

Verdict: ACCEPTED

Test 10

Group: 1

Verdict: ACCEPTED

Test 11

Group: 1

Verdict: ACCEPTED

Test 12

Group: 1

Verdict: ACCEPTED

Test 13

Group: 1

Verdict: ACCEPTED

Test 14

Group: 1

Verdict: ACCEPTED

Test 15

Group: 1

Verdict: ACCEPTED

Test 16

Group: 1

Verdict: ACCEPTED

Test 17

Group: 1

Verdict: ACCEPTED

Test 18

Group: 1

Verdict: ACCEPTED

Test 19

Group: 1

Verdict: WRONG ANSWER

Test 20

Group: 1

Verdict: WRONG ANSWER

Test 21

Group: 1

Verdict: ACCEPTED

Test 22

Group: 1

Verdict: ACCEPTED

Test 23

Group: 2

Verdict: ACCEPTED

Test 24

Group: 2

Verdict: ACCEPTED

Test 25

Group: 2

Verdict: ACCEPTED

Test 26

Group: 2

Verdict: ACCEPTED

Test 27

Group: 2

Verdict: ACCEPTED

Test 28

Group: 2

Verdict: ACCEPTED

Test 29

Group: 2

Verdict: ACCEPTED

Test 30

Group: 2

Verdict: ACCEPTED

Test 31

Group: 2

Verdict: ACCEPTED

Test 32

Group: 2

Verdict: ACCEPTED

Test 33

Group: 2

Verdict: ACCEPTED

Test 34

Group: 2

Verdict: ACCEPTED

Test 35

Group: 2

Verdict: ACCEPTED

Test 36

Group: 2

Verdict: ACCEPTED

Test 37

Group: 2

Verdict: WRONG ANSWER

Test 38

Group: 2

Verdict: ACCEPTED

Test 39

Group: 2

Verdict: WRONG ANSWER

Test 40

Group: 2

Verdict: WRONG ANSWER

Test 41

Group: 2

Verdict: ACCEPTED

Test 42

Group: 2

Verdict: ACCEPTED

Test 43

Group: 2

Verdict: ACCEPTED

Test 44

Group: 2

Verdict: ACCEPTED

Test 45

Group: 3

Verdict: RUNTIME ERROR

Test 46

Group: 3

Verdict: RUNTIME ERROR

Test 47

Group: 3

Verdict: RUNTIME ERROR

Test 48

Group: 3

Verdict: RUNTIME ERROR

Test 49

Group: 3

Verdict: RUNTIME ERROR

Test 50

Group: 3

Verdict: RUNTIME ERROR

Test 51

Group: 3

Verdict: RUNTIME ERROR

Test 52

Group: 3

Verdict: RUNTIME ERROR

Test 53

Group: 3

Verdict: RUNTIME ERROR

Test 54

Group: 3

Verdict: RUNTIME ERROR

Test 55

Group: 3

Verdict: RUNTIME ERROR

terminate called after throwing an instance of 'std::bad_alloc'
  what():  std::bad_alloc

Test 56

Group: 3

Verdict: RUNTIME ERROR

Test 57

Group: 3

Verdict: RUNTIME ERROR

Test 58

Group: 3

Verdict: RUNTIME ERROR

Test 59

Group: 3

Verdict: RUNTIME ERROR

Test 60

Group: 3

Verdict: RUNTIME ERROR

Test 61

Group: 3

Verdict: RUNTIME ERROR

Test 62

Group: 3

Verdict: ACCEPTED

Test 63

Group: 3

Verdict: RUNTIME ERROR

Test 64

Group: 3

Verdict: RUNTIME ERROR

Test 65

Group: 3

Verdict: ACCEPTED

Test 66

Group: 3

Verdict: ACCEPTED