Create Felix.md

Felixgitcode · web-flow · commit df65fa073e94 · 2018-12-09T23:44:09.000+08:00
diff --git a/2018.12.06-leetcode103/Felix.md b/2018.12.06-leetcode103/Felix.md
@@ -0,0 +1,42 @@
+```javascript
+public ArrayList<ArrayList<Integer>> zigzagLevelOrder(TreeNode root) {
+		ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>();
+		Stack<TreeNode> stack1 = new Stack<TreeNode>();
+		Stack<TreeNode> stack2 = new Stack<TreeNode>();
+		int layer = 1;//层数
+		stack1.push(root);
+		while(!stack1.isEmpty() || !stack2.isEmpty()){
+			if(layer%2!=0){//奇数层
+				ArrayList<Integer> list = new ArrayList<Integer>();
+				while(!stack1.isEmpty()){
+					TreeNode node = stack1.pop();
+					if(node != null){
+						list.add(node.val);
+						stack2.push(node.left);//从左到右
+						stack2.push(node.right);
+					}
+				}
+				if(!list.isEmpty()){
+					res.add(list);
+					layer++;
+				}
+			}else{//偶数层
+				ArrayList<Integer> list = new ArrayList<Integer>();
+				while(!stack2.isEmpty()){
+					TreeNode node = stack2.pop();
+					if(node != null){
+						list.add(node.val);
+						stack1.push(node.right);//从右到左
+						stack1.push(node.left);
+					}
+				}
+				if(!list.isEmpty()){
+					res.add(list);
+					layer++;
+				}
+			}
+		}
+		
+		return res;
+    }
+```
