Submission #1564992

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Source Code Expand

#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>
#include <utility>
#include <cmath>
#include <map>
#include <set>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define INF_LL (ll)1e18
#define INF (int)1e9
#define REP(i, n) for(int i = 0;i < (n);i++)
#define FOR(i, a, b) for(int i = (a);i < (b);i++)
#define all(x) x.begin(),x.end()
using ll = long long;
using PII = pair<int, int>;

const double eps = 1e-10;

template<typename A, typename B>inline void chmin(A &a, B b){if(a > b) a = b;}
template<typename A, typename B>inline void chmax(A &a, B b){if(a < b) a = b;}

#define fs first
#define sc second

vector<int> G[114514];
map<int, int> mp;

void dfs(int v, int p){
	mp[v] = 1;
	REP(i, G[v].size()){
		if(G[v][i] == p) continue;
		dfs(G[v][i], v);
	}
}

int main(void){
	int N, K;
	cin >> N >> K;
	REP(i, K){
		int a, b;
		cin >> a >> b;
		G[b].push_back(a);
	}
	dfs(1, -1);
	cout << mp.size() << endl;
}

Submission Info

Judge Result