heozeop: longest consecutive sequence

Author: heozeop

longest-consecutive-sequence/heozeop.cpp

@@ -0,0 +1,25 @@
+// time complexity: O(n)
+// spatail complexity: O(n)
+
+class Solution {
+public:
+    int longestConsecutive(vector<int>& nums) {
+        unordered_set<int> exisingNum(nums.begin(), nums.end());
+
+        int maxLength = 0, length;
+        for(int num : nums) {
+            if(exisingNum.find(num - 1) != exisingNum.end()) {
+                continue;
+            }
+
+            length = 1;
+            while(exisingNum.find(num + length) != exisingNum.end()) {
+                ++length;
+            }
+
+            maxLength = max(maxLength, length);
+        }
+
+        return maxLength;
+    }
+};