FastPrep
Problem · String

Character Frequencies in First-Appearance Order

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Problem statement

Count the letters in text after ignoring spaces and converting every letter to lowercase.

Return one string for each distinct letter in the order of its first appearance. Format every entry as letter:count.

Function

orderedCharacterFrequencies(text: String) → String[]

Examples

Example 1

text = "Amount Characters"return = ["a:3","m:1","o:1","u:1","n:1","t:2","c:2","h:1","r:2","e:1","s:1"]

The first distinct letters are a, m, o, u, n, t, c, h, r, e, and s.

Example 2

text = "A b A"return = ["a:2","b:1"]

Case and spaces are ignored, while a remains the first distinct letter.

Constraints

  • 1 <= text.length <= 200000
  • text contains English letters and spaces.
  • text contains at least one letter.

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public String[] orderedCharacterFrequencies(String text) {
    // Write your code here.
}
text"Amount Characters"
expected["a:3", "m:1", "o:1", "u:1", "n:1", "t:2", "c:2", "h:1", "r:2", "e:1", "s:1"]
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