LeetCode-in-All
128. Longest Consecutive Sequence
Medium
Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.
You must write an algorithm that runs in O(n) time.
Example 1:
Input: nums = [100,4,200,1,3,2]
Output: 4
Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4.
Example 2:
Input: nums = [0,3,7,2,5,8,4,6,0,1]
Output: 9
Constraints:
0 <= nums.length <= 105-109 <= nums[i] <= 109
Solution
impl Solution {
pub fn longest_consecutive(nums: Vec<i32>) -> i32 {
if nums.is_empty() {
return 0;
}
let mut nums = nums;
nums.sort_unstable(); // Equivalent to Arrays.sort in Java
let mut max = i32::MIN;
let mut ths_max = 1;
for i in 0..nums.len() - 1 {
if nums[i + 1] == nums[i] + 1 {
ths_max += 1;
} else if nums[i + 1] != nums[i] {
max = max.max(ths_max);
ths_max = 1;
}
}
max.max(ths_max) // Return the maximum sequence length
}
}