From 0ecc6afcec1ece934f0016ac76d635475793b852 Mon Sep 17 00:00:00 2001
From: Eat-Swap <root@eatswap.org>
Date: Wed, 6 Jul 2022 00:09:46 +0800
Subject: [PATCH] add: 220705

---
 cpp/2207/220705.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 cpp/2207/220705.cpp

diff --git a/cpp/2207/220705.cpp b/cpp/2207/220705.cpp
new file mode 100644
index 0000000..32650e3
--- /dev/null
+++ b/cpp/2207/220705.cpp
@@ -0,0 +1,25 @@
+#include <unordered_set>
+#include <vector>
+
+/**
+ * 128. Longest Consecutive Sequence
+ * Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.
+ * You must write an algorithm that runs in O(n) time.
+ */
+
+class Solution {
+public:
+	int longestConsecutive(const std::vector<int>& nums) {
+		std::unordered_set<int> s(nums.begin(), nums.end());
+		int ans = 0;
+		for (int i : s) {
+			if (s.count(i - 1))
+				continue;
+			int cur = i, ca = 1;
+			for (; s.count(1 + cur); ++cur)
+				++ca;
+			ans = std::max(ans, ca);
+		}
+		return ans;
+	}
+};