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

Difficulty Topics

Description

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

Solution

special-array-with-x-elements-greater-than-or-equal-x.py
class Solution:
    def specialArray(self, nums: List[int]) -> int:

        n = len(nums)

        for i in range(n+1):
            c = 0
            for num in nums:
                if num >= i:
                    c += 1
            if c == i:
                return i

        return -1