124.二叉树中的最大路径和

linwt · linwt · commit c4082489734a · 2022-04-10T11:52:57.000+08:00
diff --git a/leetcode_Java/DoneTitle.txt b/leetcode_Java/DoneTitle.txt
@@ -62,6 +62,7 @@
 160. 相交链表
 169. 多数元素
 188. 买卖股票的最佳时机 IV
+199. 二叉树的右视图
 200. 岛屿数量
 203. 移除链表元素
 206. 反转链表
diff --git a/leetcode_Java/Solution0199.java b/leetcode_Java/Solution0199.java
@@ -0,0 +1,50 @@
+// 199. 二叉树的右视图
+
+
+/**
+ * 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;
+ *     }
+ * }
+ */
+
+
+/*
+102.二叉树的层序遍历，取每层最后一个节点值
+ */
+class Solution {
+    public List<Integer> rightSideView(TreeNode root) {
+        List<Integer> list = new ArrayList<>();
+        if (root == null) {
+            return list;
+        }
+        Deque<TreeNode> queue = new ArrayDeque<>();
+        queue.add(root);
+        while (!queue.isEmpty()) {
+            int count = queue.size();
+            List<Integer> sonList = new ArrayList<>();
+            while (count > 0) {
+                TreeNode node = queue.remove();
+                sonList.add(node.val);
+                if (node.left != null) {
+                    queue.add(node.left);
+                }
+                if (node.right != null) {
+                    queue.add(node.right);
+                }
+                count--;
+            }
+            list.add(sonList.get(sonList.size() - 1));
+        }
+        return list;
+    }
+}
