Create check-if-an-array-is-consecutive.cpp

Author: kamyu104

C++/check-if-an-array-is-consecutive.cpp

@@ -0,0 +1,28 @@
+// Time:  O(n)
+// Space: O(n)
+
+// hash table
+class Solution {
+public:
+    bool isConsecutive(vector<int>& nums) {
+        return (*max_element(cbegin(nums), cend(nums)) -
+                *min_element(cbegin(nums), cend(nums)) + 1) == size(nums) &&
+               size(nums) == size(unordered_set<int>(cbegin(nums), cend(nums)));
+    }
+};
+
+// Time:  O(nlogn)
+// Space: O(1)
+// sort
+class Solution2 {
+public:
+    bool isConsecutive(vector<int>& nums) {
+        sort(begin(nums), end(nums));
+        for (int i = 0; i + 1 < size(nums); ++i) {
+            if (nums[i] + 1 != nums[i + 1]) {
+                return false;
+            }
+        }
+        return true;
+    }
+};