struct Solution;
use rustgym_util::*;
trait Inorder {
fn inorder(&self, prev: &mut Option<i32>, count: &mut usize, f: &mut impl FnMut(i32, usize));
}
impl Inorder for TreeLink {
fn inorder(&self, prev: &mut Option<i32>, count: &mut usize, f: &mut impl FnMut(i32, usize)) {
if let Some(node) = self {
let node = node.borrow();
Self::inorder(&node.left, prev, count, f);
if let Some(prev_val) = prev.as_mut() {
if *prev_val == node.val {
*count += 1;
} else {
*count = 1;
*prev = Some(node.val);
}
} else {
*prev = Some(node.val);
*count = 1;
}
f(node.val, *count);
Self::inorder(&node.right, prev, count, f);
}
}
}
impl Solution {
fn find_mode(root: TreeLink) -> Vec<i32> {
let mut max = 0;
let mut count = 0;
let mut prev: Option<i32> = None;
let mut modes: Vec<i32> = vec![];
root.inorder(&mut prev, &mut count, &mut |_, count| {
max = usize::max(count, max);
});
prev = None;
count = 0;
root.inorder(&mut prev, &mut count, &mut |val, count| {
if count == max {
modes.push(val);
}
});
modes
}
}
#[test]
fn test() {
let root = tree!(1, None, tree!(2, tree!(2), None));
assert_eq!(Solution::find_mode(root), vec![2]);
}