LeetCode 100. Same Tree-优快云博客

本文链接：https://blog.youkuaiyun.com/programmer_wei/article/details/51440185

本文介绍了一种通过递归比较两个二叉树节点值及结构的方法来判断它们是否完全相同。该方法首先检查两个根节点是否都为空或者都有非空值且节点值相等，然后递归地比较左右子树。

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题目

Given two binary trees, write a function to check if they are equal or not.
Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

public class Solution100 {

    public static void main(String args[]){
        Solution100 solution100 = new Solution100();

        TreeNode treeNode0 = new TreeNode(0);
        TreeNode treeNode1 = new TreeNode(1);
        TreeNode treeNode2 = new TreeNode(2);
        TreeNode treeNode3 = new TreeNode(3);
        TreeNode treeNode4 = new TreeNode(4);
        TreeNode treeNode5 = new TreeNode(5);

        treeNode0.left  = treeNode1;
        treeNode0.right = treeNode2;
        treeNode2.left  = treeNode3;
        treeNode2.right = treeNode4;
        treeNode1.right = treeNode5;

        boolean isSame = solution100.isSameTree(treeNode0, treeNode0);
        System.out.print(isSame);
    }


    /**
     * 同时递归来做,同时传入相同位置的节点比较是否相等
     *
     */
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p==null && q==null){
            return true;
        }

        if(p!=null && q!=null && p.val==q.val){
            boolean left  = isSameTree(p.left, q.left);
            boolean right = isSameTree(p.right, q.right);
            if(left==right && left==true){
                return  true;
            }else{
                return false;
            }
        }

        return false;
    }


    static class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;
        TreeNode(int x) { val = x; }
    }
}