binary-tree-paths.go

// https://leetcode.com/problems/binary-tree-paths

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func binaryTreePaths(root *TreeNode) []string {
    result := []string{}
    findPaths(root, []int{}, &result)
    
    return result
}

func findPaths(root *TreeNode, path []int, result *[]string) {
    if root == nil {
        return
    }
    
    if root.Left != nil {
        findPaths(root.Left, append(path, root.Val), result)
    }
    
    if root.Left == nil && root.Right == nil {
        *result = append(*result, stringifyPath(append(path, root.Val)))
        return
    }
    
    if root.Right != nil {
        findPaths(root.Right, append(path, root.Val), result)
    }
}

func stringifyPath(path []int) string {
    serialized := ""
    
    for _, x := range path {
        if len(serialized) == 0 {
            serialized = fmt.Sprintf("%d", x)
        } else {
            serialized = fmt.Sprintf("%s->%d", serialized, x)
        }
    }
    
    return serialized
}