Created
December 8, 2017 14:10
-
-
Save amwmedia/251c1939e65b1f5bdb122da787829f27 to your computer and use it in GitHub Desktop.
Advent Of Code 2017 - Day 3
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function getDist(num) { | |
let sqrt = Math.ceil(Math.sqrt(num)); | |
let sideLengthOfSq = (sqrt % 2 === 0 ? sqrt + 1 : sqrt); | |
let highestNumInSq = sideLengthOfSq * sideLengthOfSq; | |
let targetDistFromCorner = (highestNumInSq - num) % (sideLengthOfSq - 1); | |
let targetDistFromSideCenter = Math.abs(targetDistFromCorner - Math.floor(sideLengthOfSq/2)); | |
const closestDistFromSq = (sideLengthOfSq - 1) / 2; | |
return closestDistFromSq + targetDistFromSideCenter; | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function getFirstValueAbove(num) { | |
const grid = {0:{0:1}}; | |
const getNum = (x, y) => (grid[x] || {})[y] || 0; | |
const setNum = (x, y, n) => { | |
grid[x] = grid[x] || {}; | |
grid[x][y] = n; | |
return n; | |
}; | |
const sumAroundPos = (x, y) => ( | |
getNum(x, y-1) + getNum(x+1, y-1) + getNum(x-1, y-1) | |
+ getNum(x+1, y) + getNum(x-1, y) | |
+ getNum(x, y+1) + getNum(x+1, y+1) + getNum(x-1, y+1) | |
); | |
const calculateNextMove = (x, y) => { | |
const [north, south, east, west] = [[x, y+1], [x, y-1], [x+1, y], [x-1, y]]; | |
const [n, s, e, w] = [north, south, east, west].map(([px, py]) => getNum(px, py)); | |
if (n && !s && !e) { return east; } | |
if (!n && w && !e) { return north; } | |
if (!n && !w && s) { return west; } | |
if (!w && !s && e) { return south; } | |
}; | |
let n = getNum(0, 0); | |
for(let x = 0, y = 0; n < num;) { | |
// decide what square is next in line | |
const [nextX, nextY] = calculateNextMove(x, y); | |
// calculate and fill square amount | |
n = setNum(nextX, nextY, sumAroundPos(nextX, nextY)); | |
// set new current position to the new square | |
x = nextX; y = nextY; | |
} | |
return n; | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment