leetcode-----128. 最长连续序列

• 链接：https://leetcode-cn.com/problems/longest-consecutive-sequence/

代码

/*
 * @lc app=leetcode.cn id=128 lang=cpp
 *
 * [128] 最长连续序列
 */

// @lc code=start
class Solution {
public:
    int longestConsecutive(vector<int>& nums) {
        unordered_set<int> S;
        for (auto x : nums) S.insert(x);
        int ans = 0;
        for (auto x: nums) {
            if (S.count(x) && !S.count(x - 1)) {
                int y = x;
                S.erase(x);
                while (S.count(y + 1)) {
                    y++;
                    S.erase(y);
                }
                ans = max(ans, y - x + 1);
            }
        }
        return ans;
    }
};
// @lc code=end