From 373d037c624b39d46715520f95860e55892e06b6 Mon Sep 17 00:00:00 2001
From: Yanick Champoux <yanick@babyl.ca>
Date: Wed, 15 Dec 2021 10:34:28 -0500
Subject: [PATCH 1/2] 2021-15

---
 2021/15/part1.mjs | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 2021/15/part2.mjs | 28 ++++++++++++++++++++++++++
 2021/15/sample    | 10 ++++++++++
 2021/15/test.mjs  | 20 +++++++++++++++++++
 4 files changed, 108 insertions(+)
 create mode 100644 2021/15/part1.mjs
 create mode 100644 2021/15/part2.mjs
 create mode 100644 2021/15/sample
 create mode 100644 2021/15/test.mjs

diff --git a/2021/15/part1.mjs b/2021/15/part1.mjs
new file mode 100644
index 0000000..105a981
--- /dev/null
+++ b/2021/15/part1.mjs
@@ -0,0 +1,50 @@
+import fs from "fs-extra";
+import fp from "lodash/fp.js";
+import _ from "lodash";
+import Heap from 'heap';
+
+export const processInput = (input) => fs.readFile(input,'utf8').then(
+    content => content.split("\n").filter(x=>x).map(
+        line => line.split('').map( x => parseInt(x) )
+    )
+);
+
+export const genNeighbours = (maxX,maxY) => ([x,y]) =>
+    [
+        [1,0], [0,1],[-1,0],  [0,-1]
+].map(
+        delta => _.zip(delta,[x,y]).map(_.sum)
+    ).filter( ([x,y]) => {
+        if(x<0 || y<0 ) return false;
+        if( x>= maxX || y>= maxY ) return false;
+        return true;
+    } );
+
+export function solution(grid) {
+
+    const lowest = grid.map( () => grid[0].map(()=>9E9) );
+
+    const neighbors = genNeighbours(grid.length, grid[0].length);
+
+    const scouts = new Heap((a,b) => a.risk - b.risk);
+    scouts.push( {pos: [0,0], risk: 0 } );
+
+    let destinationRisk = () => _.last(_.last(lowest)) || 9E9;
+
+    while(scouts.size()) {
+        const {pos,risk} = scouts.pop();
+
+        for( const [x,y] of neighbors(pos) ) {
+
+            if( lowest[x][y] <= risk + grid[x][y] ) continue;
+
+            if( destinationRisk() <= risk + grid[x][y]  ) continue;
+
+            lowest[x][y] = risk + grid[x][y];
+
+            scouts.push({pos:[x,y], risk: lowest[x][y]} );
+        }
+    }
+
+    return _.last( _.last(lowest) );
+}
diff --git a/2021/15/part2.mjs b/2021/15/part2.mjs
new file mode 100644
index 0000000..3d04249
--- /dev/null
+++ b/2021/15/part2.mjs
@@ -0,0 +1,28 @@
+import fs from "fs-extra";
+import fp from "lodash/fp.js";
+import _ from "lodash";
+
+import * as p1 from './part1.mjs';
+
+export function solution(grid) {
+
+    const massive = Array.from({
+        length: 5 * grid.length }, ( ) => []
+    );
+
+    const wrap = x => x <= 9 ? x : (1+x % 10);
+
+    for ( const magX of _.range(0,5) ) {
+        for ( const magY of _.range(0,5) ) {
+            for ( const x of _.range(grid.length) ) {
+                for( const y of _.range(grid[0].length) ) {
+                    massive[x + grid[0].length * magX][
+                        y + grid.length * magY
+                    ] = wrap( grid[x][y] + magX + magY )
+                }
+            }
+        }
+    }
+
+    return p1.solution(massive);
+}
diff --git a/2021/15/sample b/2021/15/sample
new file mode 100644
index 0000000..ab80887
--- /dev/null
+++ b/2021/15/sample
@@ -0,0 +1,10 @@
+1163751742
+1381373672
+2136511328
+3694931569
+7463417111
+1319128137
+1359912421
+3125421639
+1293138521
+2311944581
diff --git a/2021/15/test.mjs b/2021/15/test.mjs
new file mode 100644
index 0000000..357d92c
--- /dev/null
+++ b/2021/15/test.mjs
@@ -0,0 +1,20 @@
+// https://adventofcode.com/2021/day/15
+
+import tap from "tap";
+import fs from "fs-extra";
+
+import * as p1 from "./part1.mjs";
+import * as p2 from "./part2.mjs";
+
+const sample = p1.processInput('sample');
+const input = p1.processInput('input');
+
+tap.test("part1", async (t) => {
+    t.equal(p1.solution(await sample), 40);
+    t.equal(p1.solution(await input), 456);
+});
+
+tap.test("part2", async (t) => {
+     t.equal(p2.solution(await sample), 315);
+    t.equal(p2.solution(await input), 2831);
+});

From f10edefcb410f48d3d5eb4090b0de042e3a4b4e1 Mon Sep 17 00:00:00 2001
From: Yanick Champoux <yanick@babyl.ca>
Date: Wed, 15 Dec 2021 10:35:12 -0500
Subject: [PATCH 2/2] refine the template

---
 2021/_templates/day/new/part1.mjs.t | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2021/_templates/day/new/part1.mjs.t b/2021/_templates/day/new/part1.mjs.t
index 7260703..7e6ee2f 100644
--- a/2021/_templates/day/new/part1.mjs.t
+++ b/2021/_templates/day/new/part1.mjs.t
@@ -5,7 +5,7 @@ import fs from "fs-extra";
 import fp from "lodash/fp.js";
 import _ from "lodash";
 
-export const processInput = (input) => input;
+export const processInput = (input) => fs.readFile(input,'utf8');
 
 export function solution(input) {
 }