part 1

2022/12/part1.js

@@ -27,6 +27,17 @@ export const findStart = (topoMap) => {
     return V(x,y);
 };
 
+export const findEnd = (topoMap) => {
+  let y;
+  let x = R.findIndex(topoMap, (row) => {
+    let z = row.indexOf("{");
+    if (z === -1) return false;
+    y = z;
+    return true;
+  });
+    return V(x,y);
+};
+
 const directions = [ [0,1], [0,-1],[1,0],[-1,0] ].map(
     d => V(...d)
 );
@@ -42,52 +53,42 @@ const isReachable = (topoMap,pos) => {
     const baseline = topoMap[pos.x][pos.y].charCodeAt(0);
 
     return (next) => {
-       return [0,1].includes(
-        topoMap[next.x][next.y].charCodeAt(0) - baseline
-    )
+return        topoMap[next.x][next.y].charCodeAt(0) - baseline <= 1;
     }
 }
 
 function findShortestPath(topoMap) {
-
     const initial = findStart(topoMap);
     initial.steps = 0;
-    initial.beenThere = [];
+    const final = findEnd(topoMap);
 
     const potentials = [ initial ];
 
-    let bestSoFar;
+    const beenThere = topoMap.map(
+        line => line.map( () => 9999 )
+    );
 
     const oom = outOfMap(topoMap.length,topoMap[0].length );
 
-    let failsafe = 100000;
+     let failsafe =  10; //topoMap.length*topoMap[0].length ;
     while( potentials.length > 0 ) {
-       // if(! failsafe--) return;
-        const pos = potentials.pop(); // depth-first
-        //console.log(pos.steps, bestSoFar);
-
-        if( bestSoFar && (bestSoFar <= pos.steps) ) continue;
+    //    if(! failsafe--) return;
+        const pos = potentials.shift(); // depth-first
 
-        if( topoMap[pos.x][pos.y] === '{' ) {
-            bestSoFar = pos.steps;
-            continue;
-        }
+        if( beenThere[pos.x][pos.y] <= pos.steps ) continue;
+        beenThere[pos.x][pos.y] = pos.steps;
 
         const next = directions.map(
             d => d.clone().add(pos)
         ).filter( R.isNot(oom ))
-         .filter( isReachable(topoMap,pos) )
-        .filter( next => !pos.beenThere.includes( next.toArray().join(',') ) );
+         .filter( isReachable(topoMap,pos) );
 
         next.forEach( n => n.steps = pos.steps + 1 );
-        next.forEach( n => n.beenThere = [
-            ...pos.beenThere, pos.toArray().join(',')
-        ] );
 
         potentials.push(...next);
     }
 
-    return bestSoFar;
+    return beenThere[final.x][final.y];
 
 }
 

2022/12/test.js

@@ -5,17 +5,16 @@ import part1, { findStart, sample, puzzleInput } from "./part1.js";
 import part2 from "./part2.js";
 
 describe("part 1", () => {
-    test( "findStart", () => {
-        expect( findStart(sample).toArray() ).toEqual(
-            [0,0]
-        )
-
-    });
-    test( "sample", async () => {
-        expect(part1(sample)).toEqual(31);
-    });
-  test.only("solution", () => {
-    expectSolution(part1(puzzleInput)).toEqual("TODO");
+  test("findStart", () => {
+    expect(findStart(sample).toArray()).toEqual([0, 0]);
+  });
+  test.only("sample", () => {
+    expect(part1(sample)).toEqual(31);
+  });
+  test.only("solution",() => {
+        const r = part1(puzzleInput);
+        expect(r).toBeLessThan(9999);
+    expectSolution(r).toEqual(361);
   });
 });