#5 Daily Problems -IsCryptSolution

Arun Pandian M
2 min readJul 23, 2020

This is my 5th day of 1 problem soving per day. This problem also belongs to array. Problems credits: Code Signal

Problem:

A cryptarithm is a mathematical puzzle for which the goal is to find the correspondence between letters and digits, such that the given arithmetic equation consisting of letters holds true when the letters are converted to digits.

You have an array of strings crypt, the cryptarithm, and an an array containing the mapping of letters and digits, solution. The array crypt will contain three non-empty strings that follow the structure: [word1, word2, word3], which should be interpreted as the word1 + word2 = word3 cryptarithm.

If crypt, when it is decoded by replacing all of the letters in the cryptarithm with digits using the mapping in solution, becomes a valid arithmetic equation containing no numbers with leading zeroes, the answer is true. If it does not become a valid arithmetic solution, the answer is false.

Note that number 0 doesn't contain leading zeroes (while for example 00 or 0123 do).

Example

For crypt = ["SEND", "MORE", "MONEY"] and

solution = [['O', '0'],
['M', '1'],
['Y', '2'],
['E', '5'],
['N', '6'],
['D', '7'],
['R', '8'],
['S', '9']]

the output should be
isCryptSolution(crypt, solution) = true.

When you decrypt "SEND", "MORE", and "MONEY" using the mapping given in crypt, you get 9567 + 1085 = 10652 which is correct and a valid arithmetic equation.

For crypt = ["TEN", "TWO", "ONE"] and

solution = [['O', '1'],
['T', '0'],
['W', '9'],
['E', '5'],
['N', '4']]

the output should be
isCryptSolution(crypt, solution) = false.

Even though 054 + 091 = 145, 054 and 091 both contain leading zeroes, meaning that this is not a valid solution.

Input/Output

  • [execution time limit] 3 seconds (java)
  • [input] array.string crypt
  • An array of three non-empty strings containing only uppercase English letters.
  • Guaranteed constraints:
    crypt.length = 3,
    1 ≤ crypt[i].length ≤ 14.
  • [input] array.array.char solution
  • An array consisting of pairs of characters that represent the correspondence between letters and numbers in the cryptarithm. The first character in the pair is an uppercase English letter, and the second one is a digit in the range from 0 to 9.
  • It is guaranteed that solution only contains entries for the letters present in crypt and that different letters have different values.
  • Guaranteed constraints:
    solution[i].length = 2,
    'A' ≤ solution[i][0] ≤ 'Z',
    '0' ≤ solution[i][1] ≤ '9',
    solution[i][0] ≠ solution[j][0], i ≠ j,
    solution[i][1] ≠ solution[j][1], i ≠ j.
  • [output] boolean
  • Return true if the solution represents the correct solution to the cryptarithm crypt, otherwise return false.

My solution:

boolean isCryptSolution(String[] crypt, char[][] solution) {BigInteger  firstword, secondWord, totalWord;for (char[] chars : solution) {crypt[0] = crypt[0].replace(chars[0], chars[1]);crypt[1] = crypt[1].replace(chars[0], chars[1]);crypt[2] = crypt[2].replace(chars[0], chars[1]);System.out.println("words: " + crypt[0] + " " + crypt[1] + " " + crypt[2]);}firstword = new BigInteger(crypt[0]);secondWord = new BigInteger(crypt[1]);totalWord = new BigInteger(crypt[2]);if ((crypt[0].startsWith("0") && crypt[0].length()!=1 )||( crypt[1].startsWith("0") && crypt[1].length()!=1 )|| (crypt[2].startsWith("0") && crypt[2].length()!=1 ))return false;return (firstword.add(secondWord).equals(totalWord));}

Just please give some claps to encourage me to continue this. Thanks . lets meet tomorrow guys

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Arun Pandian M

Senior Android developer at FundsIndia, A time investor to learn new things about Programming. Currently in a relationship with Green Bug(Android).