invert-binary-tree solution

Author: chjung99

invert-binary-tree/chjung99.java

@@ -0,0 +1,49 @@
+/**
+ * time: O(n)
+ * space: O(n)
+ */
+
+import java.util.*;
+
+/**
+ * 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 TreeNode invertTree(TreeNode root) {
+        breadthFirstSearch(root);
+        return root;
+    }
+    public void breadthFirstSearch(TreeNode node){
+        Deque<TreeNode> queue = new ArrayDeque<>();
+        if (node != null){
+            queue.add(node);
+        }
+
+        while (!queue.isEmpty()){
+            TreeNode cur = queue.remove();
+
+            TreeNode tmp = cur.left;
+            cur.left = cur.right;
+            cur.right = tmp;
+
+            if (cur.left != null){
+                queue.add(cur.left);
+            }
+            if (cur.right != null){
+                queue.add(cur.right);
+            }
+        }
+    }
+}