1760G - SlavicG's Favorite Problem - CodeForces Solution

from collections import Counter
import sys, threading 

input = lambda: sys.stdin.readline().strip()

def main():

    for _ in range(int(input())):

        n, a, b = map(int, input().split())
        
        adj = [[] for _ in range(n + 1)]
        for _ in range(n - 1):
            u, v, w = map(int, input().split())
            adj[u].append((v, w))
            adj[v].append((u, w))

        ok, cnt = False, Counter()
        
        def dfs1(u, p, xor):
            
            cnt[xor] += 1
            for v, w in adj[u]:
                if v == p:
                    continue
                dfs1(v, u, xor ^ w)
        
        for v, w in adj[b]:
            dfs1(v, b, w)

        def dfs2(u, p, xor):
            nonlocal ok 

            if u == b:
                return 

            if cnt[xor]:
                ok = True 
                return 

            for v, w in adj[u]:
                if v == p:
                    continue
                dfs2(v, u, xor ^ w)
        
        dfs2(a, -1, 0)

        print("YES" if ok else "NO")

if __name__ == '__main__':
    
    sys.setrecursionlimit(1 << 30)
    threading.stack_size(1 << 27)

    main_thread = threading.Thread(target=main)
    main_thread.start()
    main_thread.join()