Submission #26520165

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Source Code Expand

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#define pb emplace_back
#define mp std::make_pair
#define fi first
#define se second
typedef long long ll;
typedef std::pair<int, int> pii;
typedef std::pair<ll, int> pli;
typedef std::pair<ll, ll> pll;
typedef std::vector<int> vi;
typedef std::vector<ll> vll;
const ll mod = 998244353;
ll Add(ll x, ll y) { return (x+y>=mod) ? (x+y-mod) : (x+y); }
ll Mul(ll x, ll y) { return x * y % mod; }
ll Mod(ll x) { return x < 0 ? (x + mod) : (x >= mod ? (x-mod) : x); }
ll cadd(ll &x, ll y) { return x = (x+y>=mod) ? (x+y-mod) : (x+y); }
template <typename T> T Max(T x, T y) { return x > y ? x : y; }
template <typename T> T Min(T x, T y) { return x < y ? x : y; }
template <typename T>
T &read(T &r) {
	r = 0; bool w = 0; char ch = getchar();
	while(ch < '0' || ch > '9') w = ch == '-' ? 1 : 0, ch = getchar();
	while(ch >= '0' && ch <= '9') r = r * 10 + (ch ^ 48), ch = getchar();
	return r = w ? -r : r;
}
const int N = 100010;
int n, ent, head[N];
int d[N], f[N];
struct Edge {
	int next, to, v1, v2;
}e[N << 1];
inline void add(int x, int y, int w1, int w2) {
	e[++ent].to = y; e[ent].next = head[x]; e[ent].v1 = w1; e[ent].v2 = w2; head[x] = ent;
}
void dfs(int x, int fa, int h1, int h2) {
	d[x] = h1; f[x] = h2;
	for(int i = head[x]; i; i = e[i].next) {
		int v = e[i].to; if(v == fa) continue ;
		dfs(v, x, h1 ^ e[i].v1, h2 ^ e[i].v2);
	}
}
signed main() {
	read(n);
	for(int i = 1; i < n; ++i) {
		int u, v, w1, w2; read(u); read(v); read(w1); read(w2);
		add(u, v, w1, w2);
		add(v, u, w1, w2);
	}
	dfs(1, 0, 0, 0);
	int x = 0;
	for(int i = 1; i <= n; ++i) x ^= f[i] ^ d[i];
	for(int i = 1; i <= n; ++i) d[i] ^= x;
	std::sort(d + 1, d + n + 1);
	std::sort(f + 1, f + n + 1);
	for(int i = 1; i <= n; ++i)
		if(f[i] != d[i]) {
			puts("NO");
			return 0;
		}
	puts("YES");
	return 0;
}

Submission Info

Judge Result