Same Tree

Leetcode Problem 100: Same Tree

Problem Summary

Given the roots of two binary trees p and q, return true if the trees are identical — meaning they have the same structure and the same node values at every corresponding position.

Constraints:

• Both trees have between 0 and 100 nodes.
• Node values are integers in the range [-10,000, 10,000].

Techniques

• Tree
• Depth-First Search
• Breadth-First Search
• Binary Tree

Solution

export class TreeNode {
    val: number
    left: TreeNode | null
    right: TreeNode | null

    constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
        this.val = (val === undefined ? 0 : val)
        this.left = (left === undefined ? null : left)
        this.right = (right === undefined ? null : right)
    }
}

function isSameTree(p: TreeNode | null, q: TreeNode | null): boolean {
    if (!p && !q) {
        return true
    }

    if (!p || !q) {
        return false
    }

    return p.val === q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right)
}