82 lines
2.6 KiB
Java
82 lines
2.6 KiB
Java
//<p>如果二叉树每个节点都具有相同的值，那么该二叉树就是<em>单值</em>二叉树。</p>
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//
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//<p>只有给定的树是单值二叉树时，才返回 <code>true</code>；否则返回 <code>false</code>。</p>
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//
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//<p> </p>
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//
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//<p><strong>示例 1：</strong></p>
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//
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//<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/29/screen-shot-2018-12-25-at-50104-pm.png" style="height: 159px; width: 200px;"></p>
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//
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//<pre><strong>输入：</strong>[1,1,1,1,1,null,1]
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//<strong>输出：</strong>true
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//</pre>
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//
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//<p><strong>示例 2：</strong></p>
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//
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//<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2018/12/29/screen-shot-2018-12-25-at-50050-pm.png" style="height: 158px; width: 200px;"></p>
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//
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//<pre><strong>输入：</strong>[2,2,2,5,2]
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//<strong>输出：</strong>false
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//</pre>
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//
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//<p> </p>
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//
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//<p><strong>提示：</strong></p>
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//
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//<ol>
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// <li>给定树的节点数范围是 <code>[1, 100]</code>。</li>
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// <li>每个节点的值都是整数，范围为 <code>[0, 99]</code> 。</li>
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//</ol>
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//<div><div>Related Topics</div><div><li>树</li><li>深度优先搜索</li><li>广度优先搜索</li><li>二叉树</li></div></div><br><div><li>👍 121</li><li>👎 0</li></div>
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package leetcode.editor.cn;
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import com.code.leet.entiy.TreeNode;
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// 965:单值二叉树
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public class UnivaluedBinaryTree {
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public static void main(String[] args) {
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Solution solution = new UnivaluedBinaryTree().new Solution();
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// TO TEST
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}
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//leetcode submit region begin(Prohibit modification and deletion)
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/**
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* Definition for a binary tree node.
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* public class TreeNode {
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* int val;
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* TreeNode left;
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* TreeNode right;
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* TreeNode() {}
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* TreeNode(int val) { this.val = val; }
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* TreeNode(int val, TreeNode left, TreeNode right) {
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* this.val = val;
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* this.left = left;
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* this.right = right;
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* }
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* }
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*/
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class Solution {
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public boolean isUnivalTree(TreeNode root) {
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return isSame(root, root.val);
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}
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private boolean isSame(TreeNode node, int val) {
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if (node == null) {
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return true;
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}
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if (node.val != val) {
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return false;
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}
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boolean is = true;
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is = is && isSame(node.left, val);
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if (!is) {
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return false;
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}
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return is && isSame(node.right, val);
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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}
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