LeetCode-in-Java
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 <= 1000 <= nums[i] <= 1000
Solution
import java.util.Arrays;
public class Solution {
public int specialArray(int[] nums) {
Arrays.sort(nums);
int max = nums[nums.length - 1];
for (int x = 1; x <= max; x++) {
int found = 0;
int i = nums.length - 1;
while (i >= 0 && nums[i] >= x) {
i--;
found++;
}
if (found == x) {
return x;
}
}
return -1;
}
}