rust_test/src/main.rs

struct SegmentTree {
    tree: Vec<i32>,
    arr: Vec<i32>,
}

impl SegmentTree {
    pub fn new(baskets: Vec<i32>) -> Self {
        let n = baskets.len();
        let size = 2 << (32 - (n as u32 - 1).leading_zeros());
        let mut seg = SegmentTree {
            tree: vec![0; size as usize],
            arr: baskets.clone(),
        };
        seg.build(1, 0, n - 1);
        seg
    }

    fn push_up(&mut self, o: usize) {
        self.tree[o] = self.tree[o * 2].max(self.tree[o * 2 + 1]);
    }

    fn build(&mut self, o: usize, l: usize, r: usize) {
        if l == r {
            self.tree[o] = self.arr[l];
            return;
        }
        let m = (l + r) / 2;
        self.build(o * 2, l, m);
        self.build(o * 2 + 1, m + 1, r);
        self.push_up(o);
    }

    pub fn find_update(&mut self, o: usize, l: usize, r: usize, x: i32) -> Option<usize> {
        if self.tree[o] < x {
            return None;
        }
        if l == r {
            self.tree[o] = -1;
            return Some(l);
        }
        let m = (l + r) / 2;
        let mut i = self.find_update(o * 2, l, m, x);
        if i.is_none() {
            i = self.find_update(o * 2 + 1, m + 1, r, x);
        }
        self.push_up(o);
        i
    }
}
struct Solution;
impl Solution {
    pub fn num_of_unplaced_fruits( fruits: Vec<i32>, baskets: Vec<i32>) -> i32 {
        let n = baskets.len();
        let mut tree = SegmentTree::new(baskets);
        let mut ans = 0;

        for fruit in fruits.iter() {
            if tree.find_update(1,0,n-1,*fruit).is_none() {
                ans += 1;
            }
        }
        ans
    }
}

fn main() {
    let sl = Solution::num_of_unplaced_fruits(vec![4,2,5],vec![3,5,4]);
    println!("{:?}", sl);
}