Alphabet Subsequence

Description

Check whether the given string is a subsequence of the plaintext alphabet, given the following definitions:

subsequence: A is considered a subsequence of B if every element from A appears in B in the same order (not necessarily contiguous; there can be other elements in between). In other words, A can be obtained just by deleting elements from B.

Examples:
- [3, 7] is a subsequence of [2, 3, 7]
- [0, 0] is a subsequence of [9, 0, 2, 1, 0]
- [1, 2, 3] is a subsequence of [1, 2, 3]
- [8, 7] is not a subsequence of [7, 8] because the elements don’t appear in the same order
- [1, 1] is not a subsequence of [1, 2, 3] because it contains different elements
plaintext: The plaintext alphabet is a string “abcdef…xyz”.

Example

For s = "effg", the output should be alphabetSubsequence(s) = false;
For s = "cdce", the output should be alphabetSubsequence(s) = false;
For s = "ace", the output should be alphabetSubsequence(s) = true;
For s = "bxz", the output should be alphabetSubsequence(s) = true.

Input/Output

[execution time limit] 4 seconds (js)
[input] string s

Guaranteed constraints:
2 ≤ s.length ≤ 15.
[output] boolean
- true if the given string is a subsequence of the alphabet, false otherwise.

[JavaScript (ES6)] Syntax Tips

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// Prints help message to the console
// Returns a string
function helloWorld(name) {
console.log("This prints to the console when you Run Tests");
return "Hello, " + name;
}

Solution

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function alphabetSubsequence(s) {
  var isSubsequence = true;
  for (var i = 1; i < s.length; i++) {
    if (s.charCodeAt(i) <= s.charCodeAt(i - 1))
      isSubsequence = false;
  }

  return isSubsequence;
}

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Alphabet Subsequence

Description

Solution