1325. Delete Leaves With a Given Value

Given a binary tree `root` and an integer `target`, delete all the leaf nodes with value `target`.

Note that once you delete a leaf node with value `target`if it's parent node becomes a leaf node and has the value `target`, it should also be deleted (you need to continue doing that until you can't).

Example 1:

```Input: root = [1,2,3,2,null,2,4], target = 2
Output: [1,null,3,null,4]
Explanation: Leaf nodes in green with value (target = 2) are removed (Picture in left).
After removing, new nodes become leaf nodes with value (target = 2) (Picture in center).
```

Example 2:

```Input: root = [1,3,3,3,2], target = 3
Output: [1,3,null,null,2]
```

Example 3:

```Input: root = [1,2,null,2,null,2], target = 2
Output: [1]
Explanation: Leaf nodes in green with value (target = 2) are removed at each step.
```

Example 4:

```Input: root = [1,1,1], target = 1
Output: []
```

Example 5:

```Input: root = [1,2,3], target = 1
Output: [1,2,3]
```

Constraints:

• `1 <= target <= 1000`
• The given binary tree will have between `1` and `3000` nodes.
• Each node's value is between `[1, 1000]`.

1325. Delete Leaves With a Given Value
``````struct Solution;
use rustgym_util::*;

trait Postorder {
fn postorder(self, target: i32) -> Self;
}

fn postorder(self, target: i32) -> Self {
if let Some(node) = self {
let val = node.borrow().val;
let left = node.borrow_mut().left.take();
let right = node.borrow_mut().right.take();
let left = left.postorder(target);
let right = right.postorder(target);
if left.is_none() && right.is_none() && val == target {
None
} else {
tree!(val, left, right)
}
} else {
None
}
}
}

impl Solution {
root.postorder(target)
}
}

#[test]
fn test() {
let root = tree!(1, tree!(2, tree!(2), None), tree!(3, tree!(2), tree!(4)));
let target = 2;
let res = tree!(1, None, tree!(3, None, tree!(4)));
assert_eq!(Solution::remove_leaf_nodes(root, target), res);
let root = tree!(1, tree!(3, tree!(3), tree!(2)), tree!(3));
let target = 3;
let res = tree!(1, tree!(3, None, tree!(2)), None);
assert_eq!(Solution::remove_leaf_nodes(root, target), res);
let root = tree!(1, tree!(2, tree!(2, tree!(2), None), None), None);
let target = 2;
let res = tree!(1);
assert_eq!(Solution::remove_leaf_nodes(root, target), res);
}
``````