1022:从根到叶的二进制数之和

src/main/java/leetcode/editor/cn/SumOfRootToLeafBinaryNumbers.java

@@ -0,0 +1,91 @@
+//<p>给出一棵二叉树，其上每个结点的值都是&nbsp;<code>0</code>&nbsp;或&nbsp;<code>1</code>&nbsp;。每一条从根到叶的路径都代表一个从最高有效位开始的二进制数。</p>
+//
+//<ul>
+//	<li>例如，如果路径为&nbsp;<code>0 -&gt; 1 -&gt; 1 -&gt; 0 -&gt; 1</code>，那么它表示二进制数&nbsp;<code>01101</code>，也就是&nbsp;<code>13</code>&nbsp;。</li>
+//</ul>
+//
+//<p>对树上的每一片叶子，我们都要找出从根到该叶子的路径所表示的数字。</p>
+//
+//<p>返回这些数字之和。题目数据保证答案是一个 <strong>32 位 </strong>整数。</p>
+//
+//<p>&nbsp;</p>
+//
+//<p><strong>示例 1：</strong></p>
+//<img alt="" src="https://assets.leetcode.com/uploads/2019/04/04/sum-of-root-to-leaf-binary-numbers.png" />
+//<pre>
+//<strong>输入：</strong>root = [1,0,1,0,1,0,1]
+//<strong>输出：</strong>22
+//<strong>解释：</strong>(100) + (101) + (110) + (111) = 4 + 5 + 6 + 7 = 22
+//</pre>
+//
+//<p><strong>示例 2：</strong></p>
+//
+//<pre>
+//<strong>输入：</strong>root = [0]
+//<strong>输出：</strong>0
+//</pre>
+//
+//<p>&nbsp;</p>
+//
+//<p><strong>提示：</strong></p>
+//
+//<ul>
+//	<li>树中的节点数在&nbsp;<code>[1, 1000]</code>&nbsp;范围内</li>
+//	<li><code>Node.val</code>&nbsp;仅为 <code>0</code> 或 <code>1</code>&nbsp;</li>
+//</ul>
+//<div><div>Related Topics</div><div><li>树</li><li>深度优先搜索</li><li>二叉树</li></div></div><br><div><li>👍 159</li><li>👎 0</li></div>
+package leetcode.editor.cn;
+
+import com.code.leet.entiy.TreeNode;
+
+// 1022:从根到叶的二进制数之和
+public class SumOfRootToLeafBinaryNumbers {
+    public static void main(String[] args) {
+        Solution solution = new SumOfRootToLeafBinaryNumbers().new Solution();
+        // TO TEST
+    }
+    //leetcode submit region begin(Prohibit modification and deletion)
+
+    /**
+     * Definition for a binary tree node.
+     * 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 Solution {
+        public int sumRootToLeaf(TreeNode root) {
+            sum = 0;
+            if (root != null) {
+                dfs(root, 0);
+            }
+            return sum;
+        }
+
+        int sum;
+
+        private void dfs(TreeNode root, int num) {
+            num = num * 2 + root.val;
+            if (root.left == null && root.right == null) {
+                sum += num;
+                return;
+            }
+            if (root.left != null) {
+                dfs(root.left, num);
+            }
+            if (root.right != null) {
+                dfs(root.right, num);
+            }
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}

src/main/java/leetcode/editor/cn/doc/content/SumOfRootToLeafBinaryNumbers.md

@@ -0,0 +1,36 @@
+<p>给出一棵二叉树，其上每个结点的值都是&nbsp;<code>0</code>&nbsp;或&nbsp;<code>1</code>&nbsp;。每一条从根到叶的路径都代表一个从最高有效位开始的二进制数。</p>
+
+<ul>
+	<li>例如，如果路径为&nbsp;<code>0 -&gt; 1 -&gt; 1 -&gt; 0 -&gt; 1</code>，那么它表示二进制数&nbsp;<code>01101</code>，也就是&nbsp;<code>13</code>&nbsp;。</li>
+</ul>
+
+<p>对树上的每一片叶子，我们都要找出从根到该叶子的路径所表示的数字。</p>
+
+<p>返回这些数字之和。题目数据保证答案是一个 <strong>32 位 </strong>整数。</p>
+
+<p>&nbsp;</p>
+
+<p><strong>示例 1：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2019/04/04/sum-of-root-to-leaf-binary-numbers.png" />
+<pre>
+<strong>输入：</strong>root = [1,0,1,0,1,0,1]
+<strong>输出：</strong>22
+<strong>解释：</strong>(100) + (101) + (110) + (111) = 4 + 5 + 6 + 7 = 22
+</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>root = [0]
+<strong>输出：</strong>0
+</pre>
+
+<p>&nbsp;</p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li>树中的节点数在&nbsp;<code>[1, 1000]</code>&nbsp;范围内</li>
+	<li><code>Node.val</code>&nbsp;仅为 <code>0</code> 或 <code>1</code>&nbsp;</li>
+</ul>
+<div><div>Related Topics</div><div><li>树</li><li>深度优先搜索</li><li>二叉树</li></div></div><br><div><li>👍 159</li><li>👎 0</li></div>