Ceiling of a Number (medium)

Problem Statement

Given an array of numbers sorted in an ascending order, find the ceiling of a given number ‘key’. The ceiling of the ‘key’ will be the smallest element in the given array greater than or equal to the ‘key’.

Write a function to return the index of the ceiling of the ‘key’. If there isn’t any ceiling return -1.

Example 1:

Input: [4, 6, 10], key = 6
Output: 1
Explanation: The smallest number greater than or equal to '6' is '6' having index '1'.

Example 2:

Input: [1, 3, 8, 10, 15], key = 12
Output: 4
Explanation: The smallest number greater than or equal to '12' is '15' having index '4'.

Example 3:

Input: [4, 6, 10], key = 17
Output: -1
Explanation: There is no number greater than or equal to '17' in the given array.

Example 4:

Input: [4, 6, 10], key = -1
Output: 0
Explanation: The smallest

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