add 128

Author: luliyucoordinate

README.md

@@ -129,6 +129,7 @@ LeetCode
 |0125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome/) | c | [c++](./src/0125-Valid-Palindrome/0125.cpp) |[python](./src/0125-Valid-Palindrome/0125.py)|||Easy|
 |0126|[Word Ladder II](https://leetcode.com/problems/word-ladder-ii/) | c | [c++](./src/0126-Word-Ladder-II/0126.cpp) |[python](./src/0126-Word-Ladder-II/0126.py)|||Hard|
 |0127|[Word Ladder](https://leetcode.com/problems/word-ladder/) | c | [c++](./src/0127-Word-Ladder/0127.cpp) |[python](./src/0127-Word-Ladder/0127.py)|||Medium|
+|0128|[Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/) | c | [c++](./src/0128-Longest-Consecutive-Sequence/0128.cpp) |[python](./src/0128-Longest-Consecutive-Sequence/0128.py)|||Hard|
 |0129|[Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/) | c | [c++](./src/0129-Sum-Root-to-Leaf-Numbers/0129.cpp) |[python](./src/0129-Sum-Root-to-Leaf-Numbers/0129.py)|||Medium|
 |0130|[Surrounded Regions](https://leetcode.com/problems/surrounded-regions/) | c | [c++](./src/0130-Surrounded-Regions/0130.cpp) |[python](./src/0130-Surrounded-Regions/0130.py)|||Medium|
 |0131|[Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning/) | c | [c++](./src/0131-Palindrome-Partitioning/0131.cpp) |[python](./src/0131-Palindrome-Partitioning/0131.py)|||Medium|

src/0128-Longest-Consecutive-Sequence/0128.cpp

@@ -0,0 +1,18 @@
+static int x = []() {std::ios::sync_with_stdio(false); cin.tie(0); return 0; }();
+class Solution 
+{
+public:
+    int longestConsecutive(vector<int> &num) 
+    {
+        unordered_set<int> mem(num.begin(),num.end());
+        int res = 0;
+        for (int x : mem)
+        {
+            if (mem.count(x - 1)) continue;
+            int y = x + 1;
+            while (mem.count(y)) y++;
+            res = max(res, y - x);
+        }
+        return res;
+    }
+};

src/0128-Longest-Consecutive-Sequence/0128.py

@@ -0,0 +1,15 @@
+class Solution:
+    def longestConsecutive(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        nums = set(nums)
+        best = 0
+        for x in nums:
+            if x - 1 not in nums:
+                y = x + 1
+                while y in nums:
+                    y += 1
+                best = max(best, y - x)
+        return best