URL

leetcode.com/problems/path-sum-ii

Code

github.com/syohex/dotnet-study/blob/master/..

type Tree =
    | Leaf
    | Node of int * Tree * Tree

let pathSum (root: Tree) (targetSum: int) : int list list =
    let rec pathSum' node sum targetSum vals acc =
        match node with
        | Leaf ->
            if sum = targetSum then
                Set.add (vals |> List.rev) acc
            else
                acc
        | Node (v, left, right) ->
            let vals' = v :: vals
            let sum' = v + sum
            let acc' = pathSum' left sum' targetSum vals' acc
            pathSum' right sum' targetSum vals' acc'


    pathSum' root 0 targetSum [] Set.empty
    |> Set.toList