思维+手速

A. Goodbye, Ziyin!
https://codeforc.es/gym/103428/problem/A
题目给出的是一个树，但是如果不是二叉树就寄，特判就好
手慢无

#include
//#include
//#include
#define ll long long
#define mes(a,b) memset(a,b,sizeof(a))
#define ctn continue
#define ull unsigned long long
#pragma warning(disable:4996)
#define tgg cout<<"---------------"<> t;
	for (int i = 1; i <= t - 1; i++) {
		int x, y;
		cin >> x >> y;
		deg[x]++;
		deg[y]++;
	}
	int num = 0;
	bool fal = 0;
	for (int i = 1; i <= t; i++) {
		if (deg[i] <= 2 && deg[i] >= 1) {
			num++;
		}
		if (deg[i] >= 4) {
			fal = 1;
		}
	}
	if (fal) {
		cout << 0 << endl;
	}else
	cout << num << endl;
	return 0;
}