45 lines
1.0 KiB
JavaScript
45 lines
1.0 KiB
JavaScript
import fs from "fs-extra";
|
|
import fp from "lodash/fp.js";
|
|
import _ from "lodash";
|
|
|
|
import * as p1 from './part1.mjs';
|
|
|
|
function getBasinSize( [x,y], grid, seen ) {
|
|
if( seen[x][y] ) return 0;
|
|
|
|
seen[x][y] = true;
|
|
|
|
if( grid[x][y] == 9 ) return 0;
|
|
let size = 1;
|
|
|
|
const neighbours = p1.genNeighbours(grid.length,grid[0].length);
|
|
const coords = p1.genCoords(grid);
|
|
|
|
neighbours(x,y).map( n => getBasinSize(n,grid,seen) ).forEach(
|
|
x => size+=x
|
|
);
|
|
|
|
return size;
|
|
}
|
|
|
|
export function solution(grid) {
|
|
const seen = grid.map( () => [] );
|
|
let basinSizes = [];
|
|
|
|
|
|
for( const x of _.range(grid.length) ) {
|
|
for( const y of _.range(grid[x].length) ) {
|
|
if( seen[x][y] ) continue;
|
|
|
|
if( grid[x][y] == 9 ) {
|
|
seen[x][y] = true;
|
|
continue;
|
|
}
|
|
basinSizes.push( getBasinSize([x,y],grid,seen));
|
|
}
|
|
}
|
|
|
|
basinSizes.sort( (a,b) => a < b ? 1 : -1 );
|
|
return basinSizes.splice(0,3).reduce( (a,b) => a*b ) ;
|
|
}
|