LeetCode/com/zerroi/leetcode/Three20/LongestConsecutive.java

package com.zerroi.leetcode.Three20;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public class LongestConsecutive {
    public static void main(String[] args) {
        SolutionThird solutionThird = new SolutionThird();
        int res = solutionThird.longestConsecutive(new int[]{0,3,7,2,5,8,4,6,0,1});
        System.out.println("res = " + res);
    }

}
class SolutionThird {
    public int longestConsecutive(int[] nums) {
        if (nums.length == 0) return 0;

        Set<Integer> set = new HashSet<>();
        for (int num : nums) {
            set.add(num);
        }

        int longest = 0;
        for (int num : nums) {
            if (!set.contains(num - 1)) {
                int currentNum = num;
                int currentLength = 1;
                while (set.contains(currentNum + 1)) {
                    currentNum++;
                    currentLength++;
                }
                longest = Math.max(longest, currentLength);
            }
        }
        return longest;
    }
}