复习+

一些二叉树

src/main/java/cn/whaifree/leetCode/Tree/LeetCode101.java

@@ -0,0 +1,91 @@
+package cn.whaifree.leetCode.Tree;
+
+import cn.whaifree.leetCode.model.TreeNode;
+import org.junit.Test;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+/**
+ * @version 1.0
+ * @Author whai文海104
+ * @Date 2024/1/21 19:19
+ * @注释
+ */
+public class LeetCode101 {
+
+    @Test
+    public void test() {
+        TreeNode treeNode = TreeNode.constructTree(new Integer[]{1, 2, 2, 3, null,null, 3});
+        treeNode.printTree();
+        System.out.println(new Solution1().isSymmetric(treeNode));
+
+    }
+
+    class Solution {
+        public boolean isSymmetric(TreeNode root) {
+            if (root == null) {
+                return true;
+            }
+            return compare(root.left, root.right);
+        }
+
+        public boolean compare(TreeNode left, TreeNode right) {
+            // left.left 与 right.right递归
+            // left.right 与 right.left递归
+            if (left == null && right == null) {
+                return true;
+            } else if (left != null && right == null) {
+                return false;
+            } else if (left == null && right != null) {
+                return false;
+            } else if (left.val != right.val) {
+                return false;
+            }
+
+            boolean outSite = compare(left.left, right.right);
+            boolean inSite = compare(left.right, right.left);
+            return outSite && inSite;
+        }
+    }
+
+    class Solution1 {
+        public boolean isSymmetric(TreeNode root) {
+            if (root == null) {
+                return true;
+            }
+
+            Deque<TreeNode> deque = new LinkedList<>();
+            deque.add(root.left);
+            deque.add(root.right);
+            while (!deque.isEmpty()) {
+                TreeNode left = deque.pop();
+                TreeNode right = deque.pop();
+                if (left == null && right == null) {
+                    continue;
+                }
+//                else if (left == null && right != null) {
+//                    return false;
+//                } else if (left != null && right == null) {
+//                    return false;
+//                } else if (left.val != right.val) {
+//                    return false;
+//                }
+                if (left == null || right == null || left.val != right.val) {
+                    return false;
+                }
+
+                deque.add(left.left);
+                deque.add(right.right);
+                deque.add(left.right);
+                deque.add(right.left);
+
+            }
+            return true;
+        }
+
+
+
+    }
+
+}

src/main/java/cn/whaifree/leetCode/Tree/LeetCode104.java

@@ -0,0 +1,99 @@
+package cn.whaifree.leetCode.Tree;
+
+import cn.whaifree.leetCode.model.TreeNode;
+import org.junit.Test;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/1/21 20:05
+ * @注释
+ */
+public class LeetCode104 {
+
+    @Test
+    public void test() {
+        TreeNode treeNode = TreeNode.constructTree(new Integer[]{1, 2, 2, 3, null,null,null});
+        treeNode.printTree();
+        System.out.println(new Solution2().maxDepth(treeNode));
+    }
+
+    class Solution {
+
+        int depth = 0;
+        public int maxDepth(TreeNode root) {
+            if (root == null) {
+                return 0;
+            }
+            level(root, 1);
+            return depth;
+        }
+
+        public void level(TreeNode treeNode, int level) {
+            if (treeNode == null) {
+                return;
+            }
+            if (level > depth) {
+                depth = level;
+            }
+            if (treeNode.right != null) {
+                level(treeNode.right, level + 1);
+            }
+            if (treeNode.left != null) {
+                level(treeNode.left, level + 1);
+            }
+
+        }
+    }
+
+    class Solution2{
+
+        public int maxDepth(TreeNode root) {
+            if (root == null) {
+                return 0;
+            }
+            return level(root);
+        }
+
+        public int level(TreeNode treeNode) {
+            if (treeNode == null) {
+                return 0;
+            }
+            int left = level(treeNode.left) + 1;
+            int right = level(treeNode.right) + 1;
+            return Math.max(left, right);
+        }
+    }
+
+    class Solution1 {
+
+
+        public int maxDepth(TreeNode root) {
+            if (root == null) {
+                return 0;
+            }
+            int depth = 0;
+            // 右视图
+            Deque<TreeNode> deque = new ArrayDeque<>();
+            deque.add(root);
+            while (!deque.isEmpty()) {
+                int size = deque.size();
+                for (int i = 0; i < size; i++) {
+                    TreeNode pop = deque.pop();
+                    if (pop.left != null) {
+                        deque.add(pop.left);
+                    }
+                    if (pop.right != null) {
+                        deque.add(pop.right);
+                    }
+                }
+                depth++;
+            }
+            return depth;
+        }
+
+    }
+}

src/main/java/cn/whaifree/leetCode/Tree/LeetCode111.java

@@ -0,0 +1,107 @@
+package cn.whaifree.leetCode.Tree;
+
+import cn.whaifree.leetCode.model.TreeNode;
+import org.junit.Test;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/1/21 20:36
+ * @注释
+ */
+public class LeetCode111 {
+
+    @Test
+    public void test() {
+        TreeNode treeNode = TreeNode.constructTree(new Integer[]{1, 2, 2, 3, null,null,null,3});
+        treeNode.printTree();
+        System.out.println(new Solution2().minDepth(treeNode));
+    }
+
+    class Solution {
+        int minDepth = Integer.MAX_VALUE;
+        public int minDepth(TreeNode root) {
+            if (root == null) {
+                return 0;
+            }
+            getDepth(root, 1);
+            return minDepth;
+        }
+
+        void getDepth(TreeNode root, int level) {
+            if (root == null) {
+                return;
+            }
+            if (root.left != null) {
+                getDepth(root.left, level + 1);
+            }
+            if (root.right != null) {
+                getDepth(root.right, level + 1);
+            }
+            // 左右子树都为空，才表明已经到底部了
+            if (root.left == null && root.right == null && level < minDepth) {
+                minDepth = level;
+            }
+        }
+    }
+
+    class Solution1 {
+        public int minDepth(TreeNode root) {
+            return getDepth(root);
+        }
+
+        int getDepth(TreeNode root) {
+            if (root == null) {
+                return 0;
+            }
+            int right = getDepth(root.right) ;
+            int left = getDepth(root.left) ;
+            if (root.left == null && root.right != null) {
+                return right + 1;
+            }
+            if (root.right == null && root.left != null) {
+                return left + 1;
+            }
+
+            return 1 + Math.min(right, left);
+        }
+    }
+
+
+    class Solution2 {
+        public int minDepth(TreeNode root) {
+            if (root == null) {
+                return 0;
+            }
+
+            int depth = 0;
+
+            // 右视图
+            Deque<TreeNode> deque = new ArrayDeque<>();
+            deque.add(root);
+            while (!deque.isEmpty()) {
+                int size = deque.size();
+                depth++;
+                for (int i = 0; i < size; i++) {
+                    TreeNode pop = deque.pop();
+                    if (pop.left != null) {
+                        deque.add(pop.left);
+                    }
+                    if (pop.right != null) {
+                        deque.add(pop.right);
+                    }
+                    if (pop.right == null && pop.left == null) {
+                        // 从上到下第一个双节点非空就是输出
+                        return depth;
+                    }
+                }
+
+            }
+            return 0;
+        }
+
+    }
+}

src/main/java/cn/whaifree/leetCode/Tree/LeetCode559.java

@@ -0,0 +1,79 @@
+package cn.whaifree.leetCode.Tree;
+
+import cn.whaifree.leetCode.model.Node;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/1/21 20:20
+ * @注释
+ */
+public class LeetCode559 {
+
+    @Test
+    public void test() {
+        Node node = new Node(1);
+        node.children = new LinkedList<>();
+        node.children.add(new Node(2));
+        node.children.add(new Node(3));
+        node.children.add(new Node(4));
+        node.children.get(2).children = new ArrayList<>();
+        node.children.get(2).children.add(new Node(6));
+        node.children.get(2).children.add(new Node(7));
+
+        System.out.println(new Solution1().maxDepth(node));
+    }
+
+    class Solution {
+        public int maxDepth(Node root) {
+            return getDepth(root);
+        }
+
+        public int getDepth(Node root) {
+            if (root == null) {
+                return 0;
+            }
+            int max = 1;
+
+            List<Node> children = root.children;
+            if (children != null) {
+                for (Node child : children) {
+                    max = Math.max(getDepth(child) + 1, max);
+                }
+            }
+            return max;
+        }
+    }
+
+    class Solution1 {
+        int max = 0;
+        public int maxDepth(Node root) {
+            if (root == null) {
+                return 0;
+            }
+            getDepth(root, 1);
+            return max;
+        }
+
+        public void getDepth(Node root,int level) {
+            if (root == null) {
+                return;
+            }
+            if (level > max) {
+                max = level;
+            }
+            List<Node> children = root.children;
+            if (children != null) {
+                for (Node child : children) {
+                    getDepth(child, level + 1);
+                }
+            }
+        }
+    }
+
+}

src/main/java/cn/whaifree/redo/redo_24_1_20/LeetCode199.java

@@ -0,0 +1,71 @@
+package cn.whaifree.redo.redo_24_1_20;
+
+import cn.whaifree.leetCode.model.TreeNode;
+import org.junit.Test;
+
+import java.util.*;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/1/20 19:01
+ * @注释
+ */
+public class LeetCode199 {
+    @Test
+    public void test() {
+        TreeNode root = TreeNode.constructTree(new Integer[]{1, 2, 3, null, 5, null, 4});
+        root.printTree();
+        List<Integer> integers = new Solution1().rightSideView(root);
+        System.out.println(integers);
+    }
+
+    class Solution {
+        public List<Integer> rightSideView(TreeNode root) {
+
+            List<Integer> res = new ArrayList<>();
+            if (root == null) {
+                return res;
+            }
+
+            Deque<TreeNode> queue = new ArrayDeque<>();
+            queue.add(root);
+            while (!queue.isEmpty()) {
+                int size = queue.size();
+                for (int i = 0; i < size; i++) {
+                    TreeNode pop = queue.pop();
+                    if (i == size - 1) {
+                        res.add(pop.val);
+                    }
+                    if (pop.left!=null) queue.add(pop.left);
+                    if (pop.right!=null) queue.add(pop.right);
+                }
+            }
+            return res;
+
+        }
+    }
+
+    class Solution1 {
+
+        List<Integer> res = new LinkedList<Integer>();
+
+        public List<Integer> rightSideView(TreeNode root) {
+            level(root, 0);
+            return res;
+        }
+
+        void level(TreeNode root,int level) {
+            if (root == null) {
+                return;
+            }
+
+            if (level == res.size()) {
+                res.add(root.val);
+            }
+            if (root.right != null) level(root.right, level + 1);
+            if (root.left != null) level(root.left, level + 1);
+
+        }
+    }
+}

src/main/java/cn/whaifree/redo/redo_24_1_20/LeetCode94.java

@@ -0,0 +1,83 @@
+package cn.whaifree.redo.redo_24_1_20;
+
+import cn.whaifree.leetCode.LinkedList.LeetCode142;
+import cn.whaifree.leetCode.model.TreeNode;
+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 2024/1/20 18:37
+ * @注释
+ */
+public class LeetCode94 {
+
+    @Test
+    public void test() {
+        TreeNode root = TreeNode.constructTree(new Integer[]{1, 2, 3, 4});
+        root.printTree();
+        System.out.println(new Solution().inorderTraversal(root));
+    }
+
+    class Solution{
+        public List<Integer> inorderTraversal(TreeNode root) {
+
+            List<Integer> res = new LinkedList<>();
+            if (root == null) {
+                return res;
+            }
+
+            Deque<TreeNode> stack = new LinkedList<>();
+            stack.push(root);
+            while (!stack.isEmpty()) {
+
+                TreeNode pop = stack.pop();
+                if (pop != null) {
+                    // 中序
+//                    stack.push(pop);
+//                    stack.push(null);
+//                    if (pop.left != null) {
+//                        stack.push(pop.left);
+//                    }
+//                    if (pop.right != null) {
+//                        stack.push(pop.right);
+//                    }
+
+                    // 后序 再Reverse
+                    if (pop.left != null) {
+                        stack.push(pop.left);
+                    }
+                    if (pop.right != null) {
+                        stack.push(pop.right);
+                    }
+                    stack.push(pop);
+                    stack.push(null);
+                    // 前序
+//                    if (pop.right != null) {
+//                        stack.push(pop.right);
+//                    }
+//                    if (pop.left != null) {
+//                        stack.push(pop.left);
+//                    }
+//                    stack.push(pop);
+//                    stack.push(null);
+
+                } else {
+                    // 前序 中序
+//                    res.add(stack.pop().val);
+                    // 后序
+                    res.add(0,stack.pop().val);
+                }
+
+            }
+            return res;
+
+        }
+
+    }
+}

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode15.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 
 import org.junit.Test;

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode151.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import org.junit.Test;
 

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode18.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import org.junit.Test;
 

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode202.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import org.junit.Test;
 

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode203_false.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 
 import cn.whaifree.leetCode.model.ListNode;

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode206_false.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import cn.whaifree.leetCode.model.ListNode;
 import org.junit.Test;

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode209_false.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import org.junit.Test;
 

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode2487_false.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import cn.whaifree.leetCode.model.ListNode;
 import org.junit.Test;

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode287_false.java

@@ -1,11 +1,7 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
-import cn.hutool.core.lang.hash.Hash;
 import org.junit.Test;
 
-import java.util.HashSet;
-import java.util.Set;
-
 public class LeetCode287_false {
 
     @Test

src/main/java/cn/whaifree/redo/redo_24_1_7/LeetCode28_false.java

@@ -1,4 +1,4 @@
-package cn.whaifree.redo.redo24_1_7;
+package cn.whaifree.redo.redo_24_1_7;
 
 import org.junit.Test;