diff options
Diffstat (limited to 'bt_max_path_sum.rs')
-rw-r--r-- | bt_max_path_sum.rs | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/bt_max_path_sum.rs b/bt_max_path_sum.rs new file mode 100644 index 0000000..b0cb984 --- /dev/null +++ b/bt_max_path_sum.rs @@ -0,0 +1,38 @@ +#[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 + } + } +} |