55 lines
2.3 KiB
JavaScript
55 lines
2.3 KiB
JavaScript
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// looks like today's puzzle is the game of life but with holes in the grid
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// never programmed the game of life before but I am familiar
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const fs = require('fs');
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const data = fs.readFileSync('input.txt', 'utf-8');
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// convert seat layout to matrix of bools with padding left and right
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let layoutMat = data.split('\n').map(l=>('.'+l+'.').split('').map(s=>s=='L'));
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// create padding on top and bottom
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layoutMat.unshift(new Array(layoutMat[0].length).fill(false));
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layoutMat.push(new Array(layoutMat[0].length).fill(false));
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function iterate (stateMat, layoutMat){
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let nextState = stateMat.map(r => r.slice());
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for (let y = 1; y < layoutMat.length - 1; y++) {
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for (let x = 1; x < layoutMat[1].length - 1; x++) {
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if (!layoutMat[y][x]) continue // if this point is the floor, skip
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// count how many adjacent seats are full
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let adjSeatsFull = stateMat[y-1][x-1] + stateMat[y-1][x ] + stateMat[y-1][x+1] +
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stateMat[y ][x-1] + stateMat[y ][x+1] +
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stateMat[y+1][x-1] + stateMat[y+1][x ] + stateMat[y+1][x+1];
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// update seat according to rules in the challenge
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nextState[y][x] = stateMat[y][x] ? adjSeatsFull < 4 : adjSeatsFull == 0;
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}
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}
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return nextState
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}
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// convert matrix of seats into a string for logging
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function matToString (m) {
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return m.reduce((a1, r, y) => {
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return a1 +
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r.reduce((a,full,x) => a+String(full?'#':layoutMat[y][x]?'L':'.'), '') +
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'\n'},
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'');
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}
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// compare two matricies because javascript wont do that for you
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function compareMat (m1, m2) {
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return m1.reduce((a1,v1,i)=>a1&&v1.reduce((a2,v2,j)=>a2&&v2==m2[i][j],true),true)
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}
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// create matrix of false values. this is the initial state (all empty seats)
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let stateMat = new Array(layoutMat.length).fill(new Array(layoutMat[0].length).fill(false));
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while (true) {
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// console.log(matToString(stateMat))
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// console.log(stateMat.reduce((a1,b1)=>a1+b1.reduce((a2, b2)=>a2+b2, 0), 0))
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prevState = stateMat.map(r => r.slice()); // clone the current state
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stateMat = iterate(stateMat, layoutMat); // iterate on the state
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if (compareMat(prevState, stateMat)) break // if there is no change, we are done
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}
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// log the total amount of taken seats
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console.log(stateMat.reduce((a1,b1)=>a1+b1.reduce((a2, b2)=>a2+b2, 0), 0))
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