CodeSignal interview problems https://jsfiddle.net/g6qyubs0/1/ See also https://codesignal.com/blog/interview-prep/example-codesignal-questions/

lookup.ts

const powersOf2 = (numbers: [number]): number => {
  let count: number = 0;
  const counts = {};
  const matches: [ [number] ] = [];
  
  for (let i: number = 0; i<numbers.length; i++) {
    const element = numbers[i];
    counts[element] = counts[element] ? counts[element] + 1 : 1;
    
    for (let twoPower: number = 0; twoPower < 21; twoPower++) {
      // Calculate the amount remaining to get to this power of two.
      const second_element = (1 << twoPower) - element;
      
      // If the remainder exists in our lookup table, then we have a match.
      count += counts[second_element] ? counts[second_element] : 0;
      if (counts[second_element]) {
      	matches.push([element, second_element]);
      }
    }
  }
  
  return { count, matches };
}

pattern.ts

const patternMatch = (pattern: string, source: string): number => {
  let count = 0;
  const matches = [];
  const vowels: string = 'aeiouy';
  const VOWEL: string = '0';
  const CONSONANT: string = '1';
  
  for (let i: number = 0; i<source.length - pattern.length + 1; i++) {
    let isMatch = true;
    for (let offset: number = 0; offset<pattern.length; offset++) {
      if (pattern[offset] === VOWEL && !vowels.includes(source[i + offset])) {
      	isMatch = false;
        break;
      }
      else if (pattern[offset] === CONSONANT && vowels.includes(source[i + offset])) { 
      	isMatch = false;
      	break;
      }
    }
    
    count += isMatch ? 1 : 0;
    if (isMatch) {
    	matches.push(source.substring(i, i + pattern.length));
    }
  }
  
  return { count, matches };
};

zclient.ts

console.log(patternMatch('010', 'amazing'));
console.log(patternMatch('100', 'codesignal'));
console.log(patternMatch('110', 'frosty'));
console.log(patternMatch('0110', 'thisisalongsentence'));

/*
{
  count: 2,
  matches: ["ama", "azi"]
}
{
  count: 0,
  matches: []
}
{
  count: 2,
  matches: ["fro", "sty"]
}
{
  count: 2,
  matches: ["ente", "ence"]
}
*/

console.log(powersOf2([1, -1, 2, 3])); // 5
console.log(powersOf2([-2, -1, 0, 1, 2)); // 5
console.log(powersOf2([3, 5, 7, 9])); // 2

/*
{
  count: 5,
  matches: [[1, 1], [2, -1], [2, 2], [3, -1], [3, 1]]
}
{
  count: 5,
  matches: [[1, 0], [1, 1], [2, -1], [2, 0], [2, 2]]
}
{
  count: 2,
  matches: [[5, 3], [9, 7]]
}
*/