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You have been given a Binary Tree of * 'n'* nodes, where the nodes have integer values

Print the left view of the binary tree.

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If the input tree is as depicted in the picture:
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The Left View of the tree will be: 2 35 2
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Detailed explanation

```
2 35 10 2 3 5 2 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
```

```
2 35 2
```

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The test case is explained in the problem statement.
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```
1 2 3 4 5 -1 7 -1 -1 -1 -1 -1 -1
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```
1 2 4
```

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The Tree looks as follows:
1
/ \
2 3
/ \ \
4 5 7
```

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The expected time complexity is O(n).
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```
0 <= 'n' <= 10^5
1 <= 'data' <= 10^5
Where ‘n’ is the total number of nodes in the binary tree, and 'data' is the value of the binary tree node.
Time limit: 1sec
```