hwanmini.js

/**
 * @param {number[]} nums
 * @return {number}
 */
var longestConsecutive = function(nums) {
    if (nums.length === 0) return 0;

    const numSet = new Set(nums);
    let maxSequenceLength = 0;

    for (const num of numSet) {
        if (!numSet.has(num - 1)) {
            let currentNum = num;
            let currentLength = 1;

            while (numSet.has(currentNum + 1)) {
                currentNum++;
                currentLength++;
            }

            maxSequenceLength = Math.max(maxSequenceLength, currentLength);
        }
    }

    return maxSequenceLength;
};

console.log(longestConsecutive([100, 4, 200, 1, 3, 2]));
console.log(longestConsecutive([0, 3, 7, 2, 5, 8, 4, 6, 0, 1]));