LeetCode/problems/the-number-of-weak-characters-in-the-game.rs

#[derive(Debug, PartialEq, Eq)]
struct Property {
    attack: i32,
    defense: i32,
}

impl Property {
    fn is_weak(&self, rhs: &Property) -> bool {
        self.attack < rhs.attack && self.defense < rhs.defense
    }
}

impl From<&Vec<i32>> for Property {
    fn from(v: &Vec<i32>) -> Self {
        Self {
            attack: v[0],
            defense: v[1],
        }
    }
}

impl PartialOrd for Property {
    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
        match self.attack.partial_cmp(&other.attack) {
            Some(core::cmp::Ordering::Equal) => other.defense.partial_cmp(&self.defense),
            ord => ord,
        }
    }
}

impl Ord for Property {
    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
        if self.attack != other.attack {
            self.attack.cmp(&other.attack)
        } else {
            other.defense.cmp(&self.defense)
        }
    }
}

struct Acc {
    max: i32,
    count: i32,
}

impl Acc {
    fn new(m: i32) -> Acc {
        Acc { max: m, count: 0 }
    }

    fn update(self, p: &Property) -> Acc {
        if p.defense < self.max {
            Acc {
                max: self.max,
                count: self.count + 1,
            }
        } else {
            Acc {
                max: p.defense,
                count: self.count,
            }
        }
    }
}

impl Solution {
    pub fn number_of_weak_characters(properties: Vec<Vec<i32>>) -> i32 {
        let mut properties: Vec<Property> = properties.iter().map(From::from).collect();
        properties.sort();

        properties
            .iter()
            .rfold(Acc::new(properties.last().unwrap().defense), Acc::update)
            .count
    }
}
struct Solution {}

fn main() {
    println!("Hello World!");
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_example() {
        assert_eq!(
            Solution::number_of_weak_characters(vec![vec![5, 5], vec![6, 3], vec![3, 6]]),
            0
        );
    }

    #[test]
    fn test_another_example() {
        assert_eq!(
            Solution::number_of_weak_characters(vec![vec![2, 2], vec![3, 3]]),
            1
        );
    }

    #[test]
    fn test_another_another_example() {
        assert_eq!(
            Solution::number_of_weak_characters(vec![vec![1, 5], vec![10, 4], vec![4, 3]]),
            1
        );
    }

    #[test]
    fn test_bigger_example() {
        assert_eq!(
            Solution::number_of_weak_characters(vec![
                vec![1, 5],
                vec![10, 4],
                vec![4, 3],
                vec![2, 6],
                vec![1, 1],
                vec![10, 6]
            ]),
            3
        );
    }
}