Same Tree

1package pkg5leetcode.blind75;2 3/*4 * Same Tree | LC 1005 * APPROACH: Recursive compare values and subtrees.6 * COMPLEXITY: Time O(n), Space O(h)7 */8public class blind75_LC100SameTree {9    /** Same shape as pkg5leetcode/common/TreeNode.java (nested for single-file runs). */10 11    static class TreeNode {12        int val;13        TreeNode left, right;14        TreeNode(int val) { this.val = val; }15    }16 17    static boolean isSameTree(TreeNode p, TreeNode q) {18        if (p == null || q == null) return p == q;19        return p.val == q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right);20    }21 22    public static void main(String[] args) {23        TreeNode a = new TreeNode(1); a.left = new TreeNode(2); a.right = new TreeNode(3);24        TreeNode b = new TreeNode(1); b.left = new TreeNode(2); b.right = new TreeNode(3);25        check(isSameTree(a, b), "case1");26        TreeNode c = new TreeNode(1); c.left = new TreeNode(2);27        TreeNode d = new TreeNode(1); d.right = new TreeNode(2);28        check(!isSameTree(c, d), "case2");29        System.out.println("all tests passed");30    }31 32    static void check(boolean cond, String name) {33        if (!cond) throw new AssertionError("FAILED: " + name);34        System.out.println("  PASS " + name);35    }36}