Google Coding Competition, Pattern matching, Round 1A 2020

patternMatching.js

// https://codingcompetitions.withgoogle.com/codejam/round/000000000019fd74/00000000002b3034

function readInput() {
  const readline = require('readline')
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    terminal: false
  })

  let problem = {
    T: 0,
    testCases: []
  }
  
  let currentTestCase = null;

  rl.on('line', function (line) {
    if (problem.T === 0) {
      // Get number of test cases from first line
      problem.T = Number(line)
    } else {
      // Get number of matches
      if (!currentTestCase) {
        currentTestCase = { P: Number(line), patterns: [] }
        problem.testCases.push(currentTestCase)
      } else {
        currentTestCase.patterns.push(line.replace(/\*+/g, '*'))
      }
      if(currentTestCase.patterns.length === currentTestCase.P) {
        currentTestCase = null;
      }
    }
  })

  .on('close', () => {
    // Finished processing input, now solve question
    solveProblem(problem)
    process.exit()
  })
}

function extractStart(str) {
  let p = str.indexOf('*');
  if (p > -1) {
    return str.substr(0, p) 
  }
  return str
}

function extractEnd(str) {
  let p = str.lastIndexOf('*');
  if (p > -1) {
    return str.substr(p+1) 
  }
  return str
}

function extractMiddle(str) {
  let s = str.indexOf('*');
  let e = str.lastIndexOf('*');
  if (s > -1 && e > -1 && e != s) {
    return str.substr(s, e).replace(/\*/g, '')
  }
  return ''
}

function addToStart(word, str) {
  if (!word.start) {
    word.start = str
  } else {
    if (word.start.length >= str.length) {
      if (!word.start.includes(str)) {
        throw (word.start + ' does not include ' + str)
      }
    } else {
      if (!str.includes(word.start)) {
        throw (str + ' does not include ' + word.start)
      }
      word.start = str
    }
  }
}

function addToEnd(word, str) {
  if (!word.end) {
    word.end = str
  } else {
    if (word.end.length >= str.length) {
      if (!word.end.includes(str)) {
        throw (word.end + ' does not include ' + str)
      }
    } else {
      if (!str.includes(word.end)) {
        throw (str + ' does not include ' + word.end)
      }
      word.end = str
    }
  }
}

function handleTestCase(testcase) {
  let word = {start: '', middle: '', end: ''}
  for(let pattern of testcase.patterns) {
    if (pattern[0] != '*') {
      addToStart(word, extractStart(pattern))
    }
    if (pattern[pattern.length-1] != '*') {
      addToEnd(word, extractEnd(pattern))
    }
    word.middle = word.middle + extractMiddle(pattern)
  }
  if (word.start === word.end && ! word.middle) {
    return word.start
  }
  return word.start + word.middle + word.end
}

function solveProblem(problem) {
    let caseNb = 1;
    for(let testcase of problem.testCases) {
      try {
        console.log(`Case #${caseNb}: ${handleTestCase(testcase)}`)
      } catch (e) {
        console.log(`Case #${caseNb}: *`)
      }
      caseNb++;
    }
}

readInput()