feat(LeetCode117): 添加LeetCode117题解

feat(LeetCode129): 添加LeetCode129题解
二叉树

ForJdk17/src/main/java/cn/whaifree/leetCode/Tree/LeetCode117.java

@@ -0,0 +1,103 @@
+package cn.whaifree.leetCode.Tree;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/15 11:16
+ * @注释
+ */
+public class LeetCode117 {
+
+    class Node {
+        public int val;
+        public Node left;
+        public Node right;
+        public Node next;
+
+        public Node() {}
+
+        public Node(int _val) {
+            val = _val;
+        }
+
+        public Node(int _val, Node _left, Node _right, Node _next) {
+            val = _val;
+            left = _left;
+            right = _right;
+            next = _next;
+        }
+    }
+
+    @Test
+    public void test() {
+        Node root = new Node(1);
+        root.left = new Node(2);
+        root.right = new Node(3);
+        root.left.left = new Node(4);
+        root.left.right = new Node(5);
+        root.right.right = new Node(7);
+        root = new Solution1().connect(root);
+        System.out.println(root);
+    }
+
+    class Solution {
+
+        List<Node> levelHead = new ArrayList<>();
+
+        public Node connect(Node root) {
+            level(root, 0);
+            return root;
+        }
+
+        public void level(Node root, int level) {
+            if (root == null) {
+                return;
+            }
+
+            if (levelHead.size() > level) {
+                root.next = levelHead.get(level);
+                levelHead.set(level, root);
+            }else {
+                levelHead.add(level, root);
+            }
+            level(root.right, level + 1);
+            level(root.left, level + 1);
+        }
+    }
+
+
+    class Solution1 {
+        public Node connect(Node root) {
+
+            if (root == null) {
+                return null;
+            }
+            Deque<Node> queue = new LinkedList<>();
+            queue.add(root);
+            while (!queue.isEmpty()) {
+                int size = queue.size();
+                Node nodeIndex = null;
+                // 遍历这一层
+                for (int i = 0; i < size; i++) {
+                    Node pop = queue.pop();
+                    pop.next = nodeIndex;
+                    nodeIndex = pop;
+                    if (pop.right != null) {
+                        queue.add(pop.right);
+                    }
+                    if (pop.left != null) {
+                        queue.add(pop.left);
+                    }
+                }
+            }
+            return root;
+        }
+    }
+}

ForJdk17/src/main/java/cn/whaifree/leetCode/Tree/LeetCode129.java

@@ -0,0 +1,38 @@
+package cn.whaifree.leetCode.Tree;
+
+import cn.whaifree.leetCode.model.TreeNode;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/10/15 12:34
+ * @注释
+ */
+
+
+public class LeetCode129 {
+
+
+    /**
+     * 向下遍历，从前往后获取值
+     */
+    class Solution {
+
+        public int sumNumbers(TreeNode root) {
+            return level(root, 0);
+        }
+
+        public int level(TreeNode root,int preV) {
+            if (root == null) {
+                return 0;
+            }
+            int sum = root.val + preV * 10;
+            if (root.left == null && root.right == null) {
+                return sum;
+            }
+            int right = level(root.right,sum);
+            int left = level(root.left, sum);
+            return right + left;
+        }
+    }
+}