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 ([email protected])

  * @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\n", ans?"Alice":"Bob");

	}

    return 0;

}