Submission #43986730

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Source Code Expand

// LUOGU_RID: 117668696
#include <bits/stdc++.h>
#define SZ(x) (int) x.size() - 1
#define all(x) x.begin(), x.end()
#define ms(x, y) memset(x, y, sizeof x)
#define F(i, x, y) for (int i = (x); i <= (y); i++)
#define DF(i, x, y) for (int i = (x); i >= (y); i--)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
template <typename T> void chkmax(T& x, T y) { x = max(x, y); }
template <typename T> void chkmin(T& x, T y) { x = min(x, y); }
template <typename T> void read(T &x) {
	x = 0; int f = 1; char c = getchar();
	for (; !isdigit(c); c = getchar()) if (c == '-') f = -f;
	for (; isdigit(c); c = getchar()) x = x * 10 + c - '0';
	x *= f;
}
const int N = 2e5 + 10;
int n, sg[N];
vector <int> v[N];
void dfs(int x, int fa) {
	for (int i: v[x])
		if (i != fa) {
			dfs(i, x);
			sg[x] ^= sg[i] + 1;
		}
}
signed main() {
	read(n);
	F(i, 1, n - 1) {
		int x, y; read(x), read(y);
		v[x].push_back(y);
		v[y].push_back(x);
	}
	dfs(1, 0);
	puts(sg[1] ? "Alice" : "Bob");
	return 0;
}

Submission Info

Judge Result