Word Frequency Counter

Given a string 'S' consisting of words, your task is to calculate how many times each word appears in the string. A word is a series of one or more non-space characters. In 'S', words can be separated by spaces, and you may have leading or trailing spaces.

Input:

"what we think we become"

Output:

what 1
we 2
think 1
become 1

Example:

Consider the string: "what we think we become". Here, the word "what", "think", and "become" appear once, while "we" appears twice.

Constraints:

• 0 <= |S| <= 10^5
• Time Limit: 1 second

Note:

The output can be in any order.