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CSES Problem Set

Path Queries

Task | Statistics

CSES - Path QueriesCSES - Path Queries

Time limit:1.00 s Memory limit:512 MB

You are given a rooted tree that consists of $n$ nodes. The nodes are numbered $1,2,\ldots,n$, and node $1$ is the root. Each node has a value.

Your task is to process following types of queries:
  1. change the value of node $s$ to $x$
  2. calculate the sum of values on the path from the root to node $s$

The first input line contains two integers $n$: the number of nodes and queries. The nodes are numbered $1,2,\ldots,n$.

The next line has $n$ integers $v_1,v_2,\ldots,v_n$: the value of each node.

Then there are $n-1$ lines that describe the edges. Each line contans two integers $a$ and $b$: there is an edge between nodes $a$ and $b$.

Finally, there are $q$ lines that describe the queries. Each query is either of the form "1 $s$ $x$" or "2 $s$".


Print the answer to each query of type 2.


5 3
4 2 5 2 1
1 2
1 3
3 4
3 5
2 4
1 3 2
2 4