2229. Check if an Array Is Consecutive

Description

Given an integer array nums, return true if nums is consecutive, otherwise return false.

An array is consecutive if it contains every number in the range [x, x + n - 1] (inclusive), where x is the minimum number in the array and n is the length of the array.

 

Example 1:

Input: nums = [1,3,4,2]
Output: true
Explanation:
The minimum value is 1 and the length of nums is 4.
All of the values in the range [x, x + n - 1] = [1, 1 + 4 - 1] = [1, 4] = (1, 2, 3, 4) occur in nums.
Therefore, nums is consecutive.

Example 2:

Input: nums = [1,3]
Output: false
Explanation:
The minimum value is 1 and the length of nums is 2.
The value 2 in the range [x, x + n - 1] = [1, 1 + 2 - 1], = [1, 2] = (1, 2) does not occur in nums.
Therefore, nums is not consecutive.

Example 3:

Input: nums = [3,5,4]
Output: true
Explanation:
The minimum value is 3 and the length of nums is 3.
All of the values in the range [x, x + n - 1] = [3, 3 + 3 - 1] = [3, 5] = (3, 4, 5) occur in nums.
Therefore, nums is consecutive.

 

Constraints:

  • 1 <= nums.length <= 105
  • 0 <= nums[i] <= 105

Solutions

Solution 1

Python Code
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class Solution:
    def isConsecutive(self, nums: List[int]) -> bool:
        mi, mx = min(nums), max(nums)
        n = len(nums)
        return len(set(nums)) == n and mx == mi + n - 1

Java Code
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class Solution {
    public boolean isConsecutive(int[] nums) {
        int mi = nums[0];
        int mx = nums[0];
        Set<Integer> s = new HashSet<>();
        for (int v : nums) {
            mi = Math.min(mi, v);
            mx = Math.max(mx, v);
            s.add(v);
        }
        int n = nums.length;
        return s.size() == n && mx == mi + n - 1;
    }
}

C++ Code
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class Solution {
public:
    bool isConsecutive(vector<int>& nums) {
        unordered_set<int> s(nums.begin(), nums.end());
        int mi = *min_element(nums.begin(), nums.end());
        int mx = *max_element(nums.begin(), nums.end());
        int n = nums.size();
        return s.size() == n && mx == mi + n - 1;
    }
};

Go Code
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func isConsecutive(nums []int) bool {
	s := map[int]bool{}
	mi, mx := slices.Min(nums), slices.Max(nums)
	for _, x := range nums {
		s[x] = true
	}
	return len(s) == len(nums) && mx == mi+len(nums)-1
}