Medium
You are given a tree rooted at node 0 that consists of n
nodes numbered from 0
to n - 1
. The tree is represented by an array parent
of size n
, where parent[i]
is the parent of node i
. Since node 0 is the root, parent[0] == -1
.
You are also given a string s
of length n
, where s[i]
is the character assigned to node i
.
We make the following changes on the tree one time simultaneously for all nodes x
from 1
to n - 1
:
y
to node x
such that y
is an ancestor of x
, and s[x] == s[y]
.y
does not exist, do nothing.x
and its current parent and make node y
the new parent of x
by adding an edge between them.Return an array answer
of size n
where answer[i]
is the size of the subtree rooted at node i
in the final tree.
A subtree of treeName
is a tree consisting of a node in treeName
and all of its descendants.
Example 1:
Input: parent = [-1,0,0,1,1,1], s = “abaabc”
Output: [6,3,1,1,1,1]
Explanation:
The parent of node 3 will change from node 1 to node 0.
Example 2:
Input: parent = [-1,0,4,0,1], s = “abbba”
Output: [5,2,1,1,1]
Explanation:
The following changes will happen at the same time:
Constraints:
n == parent.length == s.length
1 <= n <= 105
0 <= parent[i] <= n - 1
for all i >= 1
.parent[0] == -1
parent
represents a valid tree.s
consists only of lowercase English letters.class Solution {
private lateinit var finalAns: IntArray
fun findSubtreeSizes(parent: IntArray, s: String): IntArray {
val n = parent.size
val arr = s.toCharArray()
val newParent = IntArray(n)
finalAns = IntArray(n)
val tree = HashMap<Int, ArrayList<Int>>()
for (i in 1 until n) {
var parentNode = parent[i]
newParent[i] = parentNode
while (parentNode != -1) {
if (arr[parentNode] == arr[i]) {
newParent[i] = parentNode
break
}
parentNode = parent[parentNode]
}
}
for (i in 1 until n) {
if (!tree.containsKey(newParent[i])) {
tree.put(newParent[i], ArrayList<Int>())
}
tree[newParent[i]]!!.add(i)
}
findNodes(0, tree)
return finalAns
}
private fun findNodes(parent: Int, tree: HashMap<Int, ArrayList<Int>>): Int {
var count = 1
if (tree.containsKey(parent)) {
for (i in tree[parent]!!) {
count += findNodes(i, tree)
}
}
finalAns[parent] = count
return count
}
}