HDU 3094 树上删边 NIM变形

基本的树上删边游戏

写过很多遍了

/** @Date    : 2017-10-13 18:19:37
  * @FileName: HDU 3094 树上删边 NIM变形.cpp
  * @Platform: Windows
  * @Author  : Lweleth (SoungEarlf@gmail.com)
  * @Link    : https://github.com/
  * @Version : $Id$
  */
#include <bits/stdc++.h>
#define LL long long
#define PII pair
#define MP(x, y) make_pair((x),(y))
#define fi first
#define se second
#define PB(x) push_back((x))
#define MMG(x) memset((x), -1,sizeof(x))
#define MMF(x) memset((x),0,sizeof(x))
#define MMI(x) memset((x), INF, sizeof(x))
using namespace std;

const int INF = 0x3f3f3f3f;
const int N = 1e5+20;
const double eps = 1e-8;

vectoredg[N];

int dfs(int x, int pre)
{
	int res = 0;
	for(auto i : edg[x])
	{
		if(i == pre) continue;
		res ^= 1 + dfs(i, x);
	}
	return res;
}

int main()
{
	int T;
	cin >> T;
	while(T--)
	{
		int n;
		scanf("%d", &n);
		for(int i = 0; i <= n; i++) edg[i].clear();
		for(int i = 0; i < n - 1; i++)
		{
			int x, y;
			scanf("%d%d", &x, &y);
			edg[x].PB(y);
			edg[y].PB(x);
		}
		int ans = dfs(1, -1);
		printf("%s
", ans?"Alice":"Bob");

	}
    return 0;
}