Description#
Given the root of a binary tree, return the sum of values of its deepest leaves.
Example 1:
Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
Output: 15
Example 2:
Input: root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]
Output: 19
Constraints:
- The number of nodes in the tree is in the range
[1, 104]. 1 <= Node.val <= 100
Solutions#
Solution 1#
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| # Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def deepestLeavesSum(self, root: Optional[TreeNode]) -> int:
q = deque([root])
while q:
ans = 0
for _ in range(len(q)):
root = q.popleft()
ans += root.val
if root.left:
q.append(root.left)
if root.right:
q.append(root.right)
return ans
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| /**
* 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 int deepestLeavesSum(TreeNode root) {
Deque<TreeNode> q = new ArrayDeque<>();
q.offer(root);
int ans = 0;
while (!q.isEmpty()) {
ans = 0;
for (int n = q.size(); n > 0; --n) {
root = q.pollFirst();
ans += root.val;
if (root.left != null) {
q.offer(root.left);
}
if (root.right != null) {
q.offer(root.right);
}
}
}
return ans;
}
}
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| /**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int deepestLeavesSum(TreeNode* root) {
int ans = 0;
queue<TreeNode*> q{{root}};
while (!q.empty()) {
ans = 0;
for (int n = q.size(); n; --n) {
root = q.front();
q.pop();
ans += root->val;
if (root->left) q.push(root->left);
if (root->right) q.push(root->right);
}
}
return ans;
}
};
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| /**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func deepestLeavesSum(root *TreeNode) int {
q := []*TreeNode{root}
ans := 0
for len(q) > 0 {
ans = 0
for n := len(q); n > 0; n-- {
root = q[0]
q = q[1:]
ans += root.Val
if root.Left != nil {
q = append(q, root.Left)
}
if root.Right != nil {
q = append(q, root.Right)
}
}
}
return ans
}
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| /**
* Definition for a binary tree node.
* class TreeNode {
* val: number
* left: TreeNode | null
* right: TreeNode | null
* constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
* }
*/
function deepestLeavesSum(root: TreeNode | null): number {
const queue = [root];
let res = 0;
while (queue.length !== 0) {
const n = queue.length;
let sum = 0;
for (let i = 0; i < n; i++) {
const { val, left, right } = queue.shift();
sum += val;
left && queue.push(left);
right && queue.push(right);
}
res = sum;
}
return res;
}
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| // Definition for a binary tree node.
// #[derive(Debug, PartialEq, Eq)]
// pub struct TreeNode {
// pub val: i32,
// pub left: Option<Rc<RefCell<TreeNode>>>,
// pub right: Option<Rc<RefCell<TreeNode>>>,
// }
//
// impl TreeNode {
// #[inline]
// pub fn new(val: i32) -> Self {
// TreeNode {
// val,
// left: None,
// right: None
// }
// }
// }
use std::rc::Rc;
use std::cell::RefCell;
impl Solution {
fn dfs(root: &Option<Rc<RefCell<TreeNode>>>, depth: i32, max_depth: &mut i32, res: &mut i32) {
if let Some(node) = root {
let node = node.borrow();
if node.left.is_none() && node.right.is_none() {
if depth == *max_depth {
*res += node.val;
} else if depth > *max_depth {
*max_depth = depth;
*res = node.val;
}
return;
}
Self::dfs(&node.left, depth + 1, max_depth, res);
Self::dfs(&node.right, depth + 1, max_depth, res);
}
}
pub fn deepest_leaves_sum(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
let mut res = 0;
let mut max_depth = 0;
Self::dfs(&root, 0, &mut max_depth, &mut res);
res
}
}
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| /**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* struct TreeNode *left;
* struct TreeNode *right;
* };
*/
void dfs(struct TreeNode* root, int depth, int* maxDepth, int* res) {
if (!root->left && !root->right) {
if (depth == *maxDepth) {
*res += root->val;
} else if (depth > *maxDepth) {
*maxDepth = depth;
*res = root->val;
}
return;
}
if (root->left) {
dfs(root->left, depth + 1, maxDepth, res);
}
if (root->right) {
dfs(root->right, depth + 1, maxDepth, res);
}
}
int deepestLeavesSum(struct TreeNode* root) {
int res = 0;
int maxDepth = 0;
dfs(root, 0, &maxDepth, &res);
return res;
}
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Solution 2#
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| # Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def deepestLeavesSum(self, root: Optional[TreeNode]) -> int:
def dfs(root, i):
nonlocal ans, mx
if root is None:
return
if i == mx:
ans += root.val
elif i > mx:
ans = root.val
mx = i
dfs(root.left, i + 1)
dfs(root.right, i + 1)
ans = mx = 0
dfs(root, 1)
return ans
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| /**
* 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 {
int mx;
int ans;
public int deepestLeavesSum(TreeNode root) {
dfs(root, 1);
return ans;
}
private void dfs(TreeNode root, int i) {
if (root == null) {
return;
}
if (i > mx) {
mx = i;
ans = root.val;
} else if (i == mx) {
ans += root.val;
}
dfs(root.left, i + 1);
dfs(root.right, i + 1);
}
}
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| /**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int mx = 0;
int ans = 0;
int deepestLeavesSum(TreeNode* root) {
dfs(root, 1);
return ans;
}
void dfs(TreeNode* root, int i) {
if (!root) return;
if (i == mx) {
ans += root->val;
} else if (i > mx) {
mx = i;
ans = root->val;
}
dfs(root->left, i + 1);
dfs(root->right, i + 1);
}
};
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| /**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func deepestLeavesSum(root *TreeNode) int {
ans, mx := 0, 0
var dfs func(*TreeNode, int)
dfs = func(root *TreeNode, i int) {
if root == nil {
return
}
if i == mx {
ans += root.Val
} else if i > mx {
mx = i
ans = root.Val
}
dfs(root.Left, i+1)
dfs(root.Right, i+1)
}
dfs(root, 1)
return ans
}
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| /**
* Definition for a binary tree node.
* class TreeNode {
* val: number
* left: TreeNode | null
* right: TreeNode | null
* constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
* }
*/
function deepestLeavesSum(root: TreeNode | null): number {
let res = 0;
let maxDepath = 0;
const dfs = ({ val, left, right }: TreeNode, depth: number) => {
if (left == null && right == null) {
if (depth === maxDepath) {
res += val;
} else if (depth > maxDepath) {
maxDepath = depth;
res = val;
}
return;
}
left && dfs(left, depth + 1);
right && dfs(right, depth + 1);
};
dfs(root, 0);
return res;
}
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