0128.最长连续序列

impl Solution {
    pub fn longest_consecutive(nums: Vec<i32>) -> i32 {
        let mut set = std::collections::HashSet::new();
        for (_, &num) in nums.iter().enumerate() {
            set.insert(num);
        }
        let mut longest = 0;
        for num in nums {
            if !set.contains(&(num - 1)) {
                let mut current = num;
                let mut current_longest = 1;
                while set.contains(&(current + 1)) {
                    current += 1;
                    current_longest += 1;
                }
                longest = std::cmp::max(longest, current_longest);
            }
        }
        longest
    }
}