提交114

Author: MistRay

leetcode/src/main/java/com/mistray/tree/FlattenBinaryTreeToLinkedList114.java

@@ -0,0 +1,60 @@
+package com.mistray.tree;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.tree
+ * @create 2020年03月05日 14:02
+ * @Desc
+ */
+public class FlattenBinaryTreeToLinkedList114 {
+
+    public void flatten(TreeNode root) {
+        if (root == null) {
+            return;
+        }
+        LinkedList<TreeNode> list = new LinkedList<>();
+        dsf(root, list);
+        TreeNode head = list.removeFirst();
+        head.left = null;
+        while (list.size() > 0) {
+            TreeNode cur = list.removeFirst();
+            cur.left = null;
+            head.right = cur;
+            head = cur;
+        }
+
+    }
+
+    public void flatten2(TreeNode root) {
+        contrary(root);
+    }
+
+
+    TreeNode pre = null;
+
+    public void contrary(TreeNode root) {
+        if (root == null) {
+            return;
+        }
+        contrary(root.right);
+        contrary(root.left);
+        root.left = null;
+        root.right = pre;
+        pre = root;
+    }
+
+
+    public void dsf(TreeNode node, LinkedList<TreeNode> list) {
+        if (node == null) {
+            return;
+        }
+        list.add(node);
+        dsf(node.left, list);
+        dsf(node.right, list);
+    }
+
+}