Codefights

A way to improve your programming skills.

View on GitHub

Is Information Consistent

Description

Court is in session. We got a group of witnesses who have all taken an oath to tell the truth. The prosecutor is pointing at the defendants one by one and asking each witnesses a simple question - “guilty or not?”. The witnesses are allowed to respond in one of the following three ways:

  • I am sure he/she is guilty.
  • I am sure he/she is innocent.
  • I have no idea.

The prosecutor has a hunch that one of the witnesses might not be telling the truth so she decides to cross-check all of their testimonies and see if the information gathered is consistent, i.e. there are no two witnesses A and B and a defendant C such that A says C is guilty while B says C is innocent.

Example

  • For

    evidences = [[ 0, 1, 0, 1], [-1, 1, 0, 0], [-1, 0, 0, 1]]

    the output should be

    isInformationConsistent(evidences) = true

  • For

    evidences = [[ 1, 0], [-1, 0], [ 1, 1], [ 1, 1]]

    the output should be

    isInformationConsistent(evidences) = false

Input/Output

  • [execution time limit] 4 seconds (js)

  • [input] array.array.integer evidences

    2-dimensional array of integers representing the set of testimonials. evidences[i][j] is the testimonial of the ith witness on the jth defendant. -1 means "innocent", 0 means "no idea", and 1 means “guilty”.

    Guaranteed constraints:
    2 ≤ evidences.length ≤ 5,
    2 ≤ evidences[0].length ≤ 10,
    evidences[i].length = evidences[j].length,
    -1 ≤ evidences[i][j] ≤ 1.

  • [output] boolean

    • true if the evidence is consistent, false otherwise.

[JavaScript (ES6)] Syntax Tips

1
2
3
4
5
6

// 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

1
2
3
4
5
6
7
8

function isInformationConsistent(evidences) {
  var transpose = evidences[0].map((_, c) =>
    evidences.map((_, i) => evidences[i][c])
  );
  return transpose.every(
    (row) => Math.max(...row) <= 0 || Math.min(...row) >= 0
  );
}