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

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.
Example 4:

Input: nums = [3,6,7,7,0]
Output: -1


Constraints:

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







class Solution {
public:
    int specialArray(vector<int>& nums) {
        int res=0;
        int n=nums.size();

        int maxi= *max_element(nums.begin(), nums.end());

        for(int i=0;i<=maxi;i++){
            int cnt=0;
            for(int j=0;j<n;j++){
                if(nums[j]>=res)
                    cnt++;
            }
            if(cnt==res) return res;
            res++;
        }

        return -1;
    }
};