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Longest Consecutive Sequence

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Linkage

https://leetcode.com/problems/longest-consecutive-sequence/description/

Code

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class Solution {
    public int longestConsecutive(int[] nums) {
        int lens = nums.length;
        if (lens == 0 || lens == 1) return lens;
        
        Set<Integer> number_set = new HashSet<Integer>();
        for (int item : nums) {
            number_set.add(item);
        }
        int index = 0;
        int max_lens = 0;
        while (!number_set.isEmpty() && index < lens) {
            int item = nums[index];
            index += 1;
            if (!number_set.contains(item)) continue;
            
            int smaller = item - 1, larger = item + 1;
            int current_lens = 1;
            number_set.remove(item);
            while(number_set.contains(smaller)) { number_set.remove(smaller); smaller -= 1; current_lens += 1; }
            while(number_set.contains(larger)) { number_set.remove(larger); larger += 1; current_lens += 1;}
            max_lens = Math.max(max_lens, current_lens);
        }
        return max_lens;
    }
    
}