Problem Statement:
Given the roots of two binary trees p and q, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical, and the nodes have the same value.
Input: p = [1,2,3], q = [1,2,3e]
Output: true
Input: p = [1,2], q = [1,null,2] Output: false
public class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode() {
}
TreeNode(int val) {
this.val = val;
}
TreeNode(int val, TreeNode left, TreeNode right) {
this.val = val;
this.left = left;
this.right = right;
}
}
class DareToDream {
public boolean isSameTree(TreeNode p, TreeNode q) {
// p and q are both null
if (p == null && q == null) return true;
// one of p and q is null
if (q == null || p == null) return false;
if (p.val != q.val) return false;
return isSameTree(p.right, q.right) && isSameTree(p.left, q.left);
}
}
Time Complexity: O(n)
Space Complexity: O(n)