2229

2229. Check if an Array Is Consecutive (Easy)

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

Companies:
Turbot

Related Topics:
Array

Similar Questions:

• Binary Tree Longest Consecutive Sequence (Medium)
• Binary Tree Longest Consecutive Sequence II (Medium)
• Consecutive Characters (Easy)

Solution 1. Sorting

// OJ: https://leetcode.com/problems/check-if-an-array-is-consecutive/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
public:
    bool isConsecutive(vector<int>& A) {
        sort(begin(A), end(A));
        for (int i = 1; i < A.size(); ++i) {
            if (A[i] != A[i - 1] + 1) return false;
        }
        return  true;
    }
};

Solution 2.

// OJ: https://leetcode.com/problems/check-if-an-array-is-consecutive/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(N)
class Solution {
public:
    bool isConsecutive(vector<int>& A) {
        int mn = *min_element(begin(A), end(A));
        vector<bool> seen(A.size());
        for (int n : A) {
            n -= mn;
            if (n < 0 || n >= A.size() || seen[n]) return false;
            seen[n] = true;
        }
        return true;
    }
};

Discuss

https://leetcode.com/problems/check-if-an-array-is-consecutive/discuss/1943451/