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#[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 {
pub fn max_path_sum(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
let mut ans = std::i32::MIN;
Solution::dfs(&root, &mut ans);
ans
}
fn dfs(node: &Option<Rc<RefCell<TreeNode>>>, ans: &mut i32) -> i32 {
if let Some(n) = node {
let val = n.borrow().val;
let l = std::cmp::max(0, Solution::dfs(&n.borrow().left, ans));
let r = std::cmp::max(0, Solution::dfs(&n.borrow().right, ans));
*ans = std::cmp::max(*ans, val + l + r);
val + std::cmp::max(l, r)
} else {
0
}
}
}
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