Binary tree isSame()

Question

Please help me review this code. I want to make it both accurate and more Go-styled.

Go Playground code

package main

import(
    "fmt"
)

type TreeNode struct {
    val int
    left *TreeNode
    right *TreeNode

}

func isSameTree(p *TreeNode , q *TreeNode ) (bool){
    if p == nil && q == nil {
        return true
    } 
    if p != nil && q == nil{
        return false;
    }
    if p ==nil && q != nil {
        return false;
    }
    if (p.val == q.val) && (isSameTree(p.left,q.left)) && (isSameTree(p.right ,q.right)){
        return true;
    } else {
        return false;
    }
}
func main(){
    p := &TreeNode{val: 1}
    p.left = &TreeNode{val: 2}
    p.right = &TreeNode{val: 3}

    q := &TreeNode{val: 1}
    q.left = &TreeNode{val: 2}
    q.right = &TreeNode{val: 3}

    isSame := isSameTree(p,q)
    fmt.Println("is same?: ", isSame)
}

Answer 1

A quick way to make your code more Go-styled is to have it automatically formatted. Specifically, spaces are a bit off. For example, in the isSameTree() signature, you have a space before a comma, a space before the closing parenthesis, and no space before the opening brace. The parentheses around (bool) are unnecessary. You're also writing semicolons inconsistently.

The isSameTree() implementation is a bit confusing ("A but not B and not C. If you made it this far, check D and E and F?"). It would be clearer as one long affirmative expression.

func isSameTree(p *TreeNode, q *TreeNode) bool {
        return (p == nil && q == nil) ||
               (p != nil && q != nil &&
                p.val == q.val &&
                isSameTree(p.left, q.left) && isSameTree(p.right, q.right))
}

Answer 2

https://play.golang.org/p/JSt3HtE29C

Changes:

• tidy the definition of TreeNode by sharing the type for left and right.
• simplify the tests for p and q being nil.
• Removing braces from the if condition
• if <x> { return true } else { return false } is better written return <x>.

Here's the changed code:

type TreeNode struct {
    val         int
    left, right *TreeNode
}

func isSameTree(p *TreeNode, q *TreeNode) bool {
    if p == nil || q == nil {
        return p == q
    }
    return p.val == q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right)
}