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feat(2023-01): don't use string replacement to parse text
"eightwo" should render as "82" not "8wo" Solves part 2
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-39
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3 files changed

+187
-39
lines changed

‎2023/day-01/checksum.js‎

Lines changed: 85 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -14,34 +14,104 @@ const checksumLine = (data) => {
1414
return parseInt(result)
1515
}
1616

17+
const lazyNums = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']
18+
const lazyReg = new RegExp(lazyNums.join('|'))
19+
const lazyNumsReversed = lazyNums.map((num) => num.split('').reverse().join(''))
20+
const lazyReversReg = new RegExp(lazyNumsReversed.join('|'))
21+
22+
const lookupPosition = (match) => {
23+
const idx = lazyNums.indexOf(match)
24+
if (idx > 9) {
25+
return idx - 9
26+
}
27+
return idx
28+
}
29+
30+
const lookupPositionReversed = (match) => {
31+
const reverseMatch = match.split('').reverse().join('')
32+
const idx = lazyNums.indexOf(reverseMatch)
33+
if (idx > 9) {
34+
return idx - 9
35+
}
36+
return idx
37+
}
38+
39+
const lazyChecksumLine = (data) => {
40+
let first = ''
41+
data.replace(lazyReg, (match) => {
42+
first = lookupPosition(match)
43+
return match // reinsert so we don't bork the data string
44+
})
45+
// find last matching digit by reversing the string and searching backwards
46+
let last = ''
47+
data = data.split('').reverse().join('')
48+
data.replace(lazyReversReg, (match) => {
49+
last = lookupPositionReversed(match)
50+
return match // reinsert so we don't bork the data string
51+
})
52+
53+
return parseInt(`${first}${last}`)
54+
}
55+
1756
/**
1857
* Generates the checksum for an entire set
1958
* @param {array} set of lines containing data
2059
*/
21-
const checksumSet = (set) => {
60+
const checksumSet = (set, sanitize = false, lazy = false) => {
61+
let filter = (data) => data
62+
if (sanitize) {
63+
filter = sanitizeLine
64+
}
65+
66+
let checksum = checksumLine
67+
if (lazy) {
68+
checksum = lazyChecksumLine
69+
}
70+
2271
return set.reduce((total, current) => {
23-
return total + checksumLine((current))
72+
return total + checksum(
73+
filter(current)
74+
)
2475
}, 0)
2576
}
2677

27-
/**
28-
* Generates the checksum for an entire set when data is not sanitized
29-
* @param {array} set of lines containing data
30-
*/
31-
const checksumUnSanitizedSet = (set) => {
32-
return set.reduce((total, current) => {
33-
return total + checksumLine(sanitizeLine(current))
34-
}, 0)
78+
const numbers = ['one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']
79+
const numbersReversed = numbers.map((num) => num.split('').reverse().join(''))
80+
const reg = new RegExp(numbers.join('|'))
81+
const regGlobal = new RegExp(numbers.join('|'), 'g')
82+
const regReversed = new RegExp(numbersReversed.join('|'))
83+
84+
// Sanitizes using a single-pass regex replace all
85+
// Produces 53885 which is incorrect for part 2
86+
const byRegex = (data) => {
87+
return data.replaceAll(regGlobal, (matched) => numbers.indexOf(matched) + 1)
88+
}
89+
90+
// Sanitizes by replacing just the first and last text digits, in case shared letters is supposed to work
91+
// Produces 53853 which is too low for part 2
92+
const byFirstLast = (data) => {
93+
// sanitize first matching digit
94+
data = data.replace(reg, (matched) => numbers.indexOf(matched) + 1)
95+
// sanitize last matching digit by reversing the string and searching backwards
96+
data = data.split('').reverse().join('')
97+
data = data.replace(regReversed, (matched) => numbersReversed.indexOf(matched) + 1)
98+
99+
// return original order
100+
return data.split('').reverse().join('')
35101
}
36102

37-
const numbers = ['zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']
38-
const reg = new RegExp(numbers.join('|'), 'g')
39103
/**
40104
* Sanitzizes a line by replacing spelled-out numbers with data
41105
* @param {string} data line of input to sanitize
42106
*/
43-
const sanitizeLine = (data) => {
44-
return data.replaceAll(reg, (matched) => numbers.indexOf(matched))
107+
const sanitizeLine = (data, method = 'byFirstLast') => {
108+
const methods = {
109+
none: (data) => data,
110+
byFirstLast,
111+
byRegex
112+
}
113+
114+
return methods[method](data)
45115
}
46116

47-
module.exports = { checksumLine, checksumSet, checksumUnSanitizedSet, sanitizeLine }
117+
module.exports = { checksumLine, checksumSet, sanitizeLine, lazyChecksumLine }

‎2023/day-01/checksum.test.js‎

Lines changed: 101 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
/* eslint-env mocha */
22
const { expect } = require('chai')
3-
const { checksumSet, checksumUnSanitizedSet, checksumLine, sanitizeLine } = require('./checksum')
3+
const { checksumSet, checksumLine, sanitizeLine, lazyChecksumLine } = require('./checksum')
44
const fs = require('fs')
55
const path = require('path')
66
const filePath = path.join(__dirname, 'input.txt')
@@ -30,7 +30,7 @@ describe('--- Day 1: Trebuchet?! ---', () => {
3030
})
3131
describe('Part 2', () => {
3232
describe('sanitizeLine', () => {
33-
const set = [
33+
const data = [
3434
'two1nine',
3535
'eightwothree',
3636
'abcone2threexyz',
@@ -41,40 +41,119 @@ describe('--- Day 1: Trebuchet?! ---', () => {
4141
]
4242
const result = [29, 83, 13, 24, 42, 14, 76]
4343
it('cleans up a string when digits are spelled out', () => {
44+
const set = JSON.parse(JSON.stringify(data))
4445
for (let x = 0; x < set.length; x++) {
4546
expect(checksumLine(sanitizeLine(set[x]))).to.equal(result[x])
47+
// expect(checksumLine(sanitizeLine(set[x], 'sanitizeByRegex'))).to.equal(result[x])
48+
// expect(checksumLine(sanitizeLine(set[x], 'sanitizeFirstLast'))).to.equal(result[x])
4649
}
4750
})
48-
it('handles first matches, and doesn\'t allow for multiple words to share letters', () => {
49-
expect(sanitizeLine('eightwothree')).to.equal('8wo3')
51+
it('allows for skipping sanitation', () => {
52+
const set = JSON.parse(JSON.stringify(data))
53+
for (let x = 0; x < set.length; x++) {
54+
expect(sanitizeLine(set[x], 'none')).to.equal(data[x])
55+
}
5056
})
5157
})
52-
describe('checksumUnSanitizedSet', () => {
53-
it('calculates the checksum for a set of lines by summing the checksum of each sanitized line', () => {
54-
const set = [
55-
'two1nine',
56-
'eightwothree',
57-
'abcone2threexyz',
58-
'xtwone3four',
59-
'4nineeightseven2',
60-
'zoneight234',
61-
'7pqrstsixteen'
62-
]
63-
expect(checksumUnSanitizedSet(set)).to.equal(281)
58+
describe('checksumSet', () => {
59+
const data = [
60+
'two1nine',
61+
'eightwothree',
62+
'abcone2threexyz',
63+
'xtwone3four',
64+
'4nineeightseven2',
65+
'zoneight234',
66+
'7pqrstsixteen'
67+
]
68+
it('can sanitize', () => {
69+
expect(checksumSet(data, true)).to.equal(281)
6470
})
6571
})
72+
describe('lazyChecksumLine', () => {
73+
const data = [
74+
'two1nine',
75+
'eightwothree',
76+
'abcone2threexyz',
77+
'xtwone3four',
78+
'4nineeightseven2',
79+
'zoneight234',
80+
'7pqrstsixteen'
81+
]
82+
const result = [29, 83, 13, 24, 42, 14, 76]
83+
it('can match text or numeric for checksum calcs', () => {
84+
const set = JSON.parse(JSON.stringify(data))
85+
for (let x = 0; x < set.length; x++) {
86+
expect(lazyChecksumLine(set[x])).to.equal(result[x])
87+
}
88+
})
89+
})
90+
91+
// it('doesn`t sanitize by default', () => {
92+
// const set = [
93+
// 'two1nine',
94+
// 'eightwothree',
95+
// 'abcone2threexyz',
96+
// 'xtwone3four',
97+
// '4nineeightseven2',
98+
// 'zoneight234',
99+
// '7pqrstsixteen'
100+
// ]
101+
// expect(checksumSet(set)).to.be.NaN
102+
// })
103+
// it('allows for sanitizing to be explicitly disabled', () => {
104+
// const set = [
105+
// 'two1nine',
106+
// 'eightwothree',
107+
// 'abcone2threexyz',
108+
// 'xtwone3four',
109+
// '4nineeightseven2',
110+
// 'zoneight234',
111+
// '7pqrstsixteen'
112+
// ]
113+
// expect(checksumSet(set, 'none')).to.be.NaN
114+
// })
115+
// // it('calculates the checksum for a set of lines by summing the checksum of each line', () => {
116+
// // const set = [
117+
// // 'two1nine',
118+
// // 'eightwothree',
119+
// // 'abcone2threexyz',
120+
// // 'xtwone3four',
121+
// // '4nineeightseven2',
122+
// // 'zoneight234',
123+
// // '7pqrstsixteen'
124+
// // ]
125+
// // expect(checksumSet(set)).to.equal(281)
126+
// // })
127+
// })
66128
describe('integeration', () => {
67-
it('53853 is too low for part 2', (done) => {
68-
let data
69-
fs.readFile(filePath, { encoding: 'utf8' }, (err, initData) => {
129+
let initData
130+
before((done) => {
131+
fs.readFile(filePath, { encoding: 'utf8' }, (err, rawData) => {
70132
if (err) throw err
71-
initData = inputToArray(initData.trim())
133+
initData = inputToArray(rawData.trim())
72134
// Deep copy to ensure we aren't mutating the original data
73-
data = JSON.parse(JSON.stringify(initData))
74-
expect(checksumUnSanitizedSet(data)).to.be.greaterThan(53853)
135+
// data = JSON.parse(JSON.stringify(initData))
75136
done()
76137
})
77138
})
139+
140+
it('is not done without sanitation, since that matches part 1', () => {
141+
const data = JSON.parse(JSON.stringify(initData))
142+
const result = checksumSet(data, true)
143+
expect(result).to.not.equal(54953)
144+
})
145+
146+
it('is not done with a one-time regex', () => {
147+
const data = JSON.parse(JSON.stringify(initData))
148+
const result = checksumSet(data, true)
149+
expect(result).to.not.equal(53885) // result of one-time regex
150+
})
151+
152+
it('is not done by sanitizing just the first and last strings', () => {
153+
const data = JSON.parse(JSON.stringify(initData))
154+
const result = checksumSet(data, true)
155+
expect(result).to.not.equal(53853) // result of first/last substitution onlye
156+
})
78157
})
79158
})
80159
})

‎2023/day-01/solution.js‎

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -21,8 +21,7 @@ fs.readFile(filePath, { encoding: 'utf8' }, (err, initData) => {
2121

2222
const part2 = () => {
2323
const data = resetInput()
24-
console.debug(data)
25-
return 'No answer yet'
24+
return checksumSet(data, false, true)
2625
}
2726
const answers = []
2827
answers.push(part1())

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