#U1920DS3. Milk Visits
Milk Visits
Farmer John is planning to build NN (1≤N≤1051≤N≤105) farms that will be connected by N−1N−1 roads, forming a tree (i.e., all farms are reachable from each-other, and there are no cycles). Each farm contains a cow, whose breed is either Guernsey or Holstein.Farmer John's MM friends (1≤M≤1051≤M≤105) often come to visit him. During a visit with friend ii, Farmer John will walk with his friend along the unique path of roads from farm AiAi to farm BiBi (it may be the case that Ai**=Bi**Ai=Bi). Additionally, they can try some milk from any cow along the path they walk. Since most of Farmer John's friends are also farmers, they have very strong preferences regarding milk. Some of his friends will only drink Guernsey milk, while the remainder will only drink Holstein milk. Any of Farmer John's friends will only be happy if they can drink their preferred type of milk during their visit.
Please determine whether each friend will be happy after visiting.
SCORING:
- Test cases 2-5 satisfy N≤103**,M≤2⋅103**.N≤103,M≤2⋅103.
INPUT FORMAT (file milkvisits.in):
The first line contains the two integers NN and MM.The second line contains a string of length NN. The iith character of the string is 'G' if the cow in the iith farm is a Guernsey, or 'H' if the cow in the iith farm is a Holstein.
The next N−1N−1 lines each contain two distinct integers XX and YY (1≤X,Y≤N1≤X,Y≤N), indicating that there is a road between farms XX and YY.
The next MM lines contain integers AiAi, BiBi, and a character CiCi. AiAi and BiBi represent the endpoints of the path walked during friend ii's visit, while CiCi is either G or H if the iith friend prefers Guernsey milk or Holstein milk.
OUTPUT FORMAT (file milkvisits.out):
Print a binary string of length MM. The iith character of the string should be '1' if the iith friend will be happy, or '0' otherwise.
SAMPLE INPUT:
5 5
HHGHG
1 2
2 3
2 4
1 5
1 4 H
1 4 G
1 3 G
1 3 H
5 5 H
SAMPLE OUTPUT:
10110
Here, the path from farm 1 and farm 4 involves farms 1, 2, and 4. All of these contain Holsteins, so the first friend will be satisfied while the second one will not.