1608_Leetcode.py

#1608. Special Array With X Elements Greater Than or Equal X
#Easy


"""

You are given an array nums of non-negative integers. nums is considered special if there exists a number x such that there are exactly x numbers in nums that are greater than or equal to x.

Notice that x does not have to be an element in nums.

Return x if the array is special, otherwise, return -1. It can be proven that if nums is special, the value for x is unique.

Example 1:

Input: nums = [3,5]
Output: 2
Explanation: There are 2 values (3 and 5) that are greater than or equal to 2.

Example 2: 

Input: nums = [0,0]
Output: -1
Explanation: No numbers fit the criteria for x.
If x = 0, there should be 0 numbers >= x, but there are 2.
If x = 1, there should be 1 number >= x, but there are 0.
If x = 2, there should be 2 numbers >= x, but there are 0.
x cannot be greater since there are only 2 numbers in nums.

Example 3:

Input: nums = [0,4,3,0,4]
Output: 3
Explanation: There are 3 values that are greater than or equal to 3.

Constraints:

1 <= nums.length <= 100
0 <= nums[i] <= 1000

"""

#------------------------------------------------------------------------------------------------------------------------------------------

class Solution:
    def specialArray(self, nums: List[int]) -> int:
        # Iterate through possible values of 'i'
        for i in range(len(nums) + 1):
            # Count how many elements in 'nums' are greater than or equal to 'i'
            count = sum(1 for num in nums if num >= i)
            # If the count matches the value of 'i', return 'i'
            if count == i:
                return i
        # If no such 'i' exists, return -1
        return -1