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(function(inp) | |
{ | |
function getNeighbours(x,y) | |
{ | |
let deltas = [ | |
[-1,0], | |
[0,-1], | |
[0,1], | |
[1,0], | |
]; | |
let neighbours = []; | |
for(let delta of deltas) | |
{ | |
let [xd, yd] = delta; | |
neighbours.push([xd+x, yd+y]); | |
} | |
return neighbours; | |
} | |
let points = inp.split('\n').map(line => line.split('')).filter(line => line.length > 0).flat().map(v => parseInt(v,10)); | |
const width = 100; | |
let lowpoints = []; | |
for(let i = 0; i < points.length; i++) | |
{ | |
let x = i % width; | |
let y = Math.floor(i / width); | |
let neighbours = getNeighbours(x,y); | |
let highercount = 0; | |
for(let neigh of neighbours) | |
{ | |
let [nx, ny] = neigh; | |
if(nx >= width || nx < 0 || ny >= width || ny < 0) | |
{ | |
highercount++; | |
continue; | |
} | |
let ni = nx + (ny * width); | |
if(points[ni] > points[i]) | |
{ | |
highercount++; | |
} | |
} | |
if(highercount == 4) | |
{ | |
lowpoints.push(points[i]); | |
} | |
} | |
return lowpoints.reduce((s,v) => s+v+1, 0); | |
})(document.querySelector('pre').textContent); |
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