All Problems

Problem title

Difficulty

Avg time to solve

Kruskal’s Minimum Spanning Tree Algorithm

Moderate

--

Mike and Mobile

Moderate

35 mins

Star Pattern

Easy

--

Split A Circular Linked List

Easy

15 mins

Find K-th smallest Element in BST

Easy

15 mins

Minimum Insertions

Moderate

20 mins

Largest Submatrix with Equal Number of 0's and 1's

Easy

15 mins

Binary Tree Zigzag Traversal

Easy

15 mins

Minimum Time To Solve The Problems

Hard

50 mins

Sort a half-sorted array

Easy

10 mins

Problem

Submissions

5

Avg. time to solve

15 min

Success Rate

85%

Problem Statement

```
In zigzag order, level 1 is printed from left to right fashion, level 2 is printed from right to left. and level 3 is printed from left to right again, and so on…..
```

```
For the given binary tree
```

```
The zigzag traversal is [1, 4, 3, 5, 2, 7, 6]
```

```
The first line contains an integer 'T' which denotes the number of test cases or queries to be run. Then the 'T' test cases follow.
The first line of each test case contains elements of the tree in the level order form. The line consists of values of nodes separated by a single space. In case a node is null, we take -1 in its place.
For example, the input for the tree depicted in the below image
```

```
1
3 8
5 2 7 -1
-1 -1 -1 -1 -1 -1
```

```
Level 1 :
The root node of the tree is 1
Level 2 :
Left child of 1 = 3
Right child of 1 = 8
Level 3 :
Left child of 3 = 5
Right child of 3 = 2
Left child of 8 =7
Right child of 8 = null (-1)
Level 4 :
Left child of 5 = null (-1)
Right child of 5 = null (-1)
Left child of 2 = null (-1)
Right child of 2 = null (-1)
Left child of 7 = null (-1)
Right child of 7 = null (-1)
The first not-null node(of the previous level) is treated as the parent of the first two nodes of the current level. The second not-null node (of the previous level) is treated as the parent node for the next two nodes of the current level and so on.
The input ends when all nodes at the last level are null(-1).
```

```
The above format was just to provide clarity on how the input is formed for a given tree.
The sequence will be put together in a single line separated by a single space. Hence, for the above-depicted tree, the input will be given as:
1 3 8 5 2 7 -1 -1 -1 -1 -1 -1 -1
```

```
For each test case, print a single line containing all the nodes value in zigzag order traversal separated by a single space in a separate line.
```

```
You do not need to print anything, it has already been taken care of. Just implement the given function.
```

```
1 <= 'T' <= 100
0 <= 'N' <= 10^3
0 <= 'NODES' <= 10^9
Where NODES represent any node value
Time Limit: 1sec
```

```
2
1 2 3 -1 -1 -1 6 -1 -1
1 2 3 -1 -1 -1 -1
```

```
1 3 2 6
1 3 2
```

```
For the first test case, the given binary tree is shown below.
```

```
zigzag traversal of given tree = [1, 3, 2, 6]
For the second test case, the given binary tree is shown below.
```

```
ZigZag traversal of given tree = [1, 3, 2]
```

```
1
1 2 4 5 3 -1 -1 -1 -1 -1 -1
```

```
1 4 2 5 3
```

```
For the first test case, the given binary tree is shown below.
```

```
ZigZag traversal of given tree = [1, 4, 2, 5, 3]
```

Java (SE 1.8)

Console

Sample Test Case

Custom Test Case

Download Test Cases

Test Case 1

Test Case 2

Test Case 3

Saving Code...

Full Screen Mode

Change Theme

Solution submission not allowed

Save Code

Reset Code