solved day 17. p2 takes 133 secs....

2023/Day_17/README.md

@@ -59,3 +59,57 @@ One way to **minimize heat loss** is this path:
 This path never moves more than three consecutive blocks in the same direction and incurs a heat loss of only **`102`**.
 
 Directing the crucible from the lava pool to the machine parts factory, but not moving more than three consecutive blocks in the same direction, **what is the least heat loss it can incur?**
+
+---
+
+## --- Part Two ---
+
+The crucibles of lava simply aren't large enough to provide an adequate supply of lava to the machine parts factory. Instead, the Elves are going to upgrade to **ultra crucibles**.
+
+Ultra crucibles are even more difficult to steer than normal crucibles. Not only do they have trouble going in a straight line, but they also have trouble turning!
+
+Once an ultra crucible starts moving in a direction, it needs to move **a minimum of four blocks** in that direction before it can turn (or even before it can stop at the end). However, it will eventually start to get wobbly: an ultra crucible can move a maximum of **ten consecutive blocks** without turning.
+
+In the above example, an ultra crucible could follow this path to minimize heat loss:
+
+```
+2>>>>>>>>1323
+32154535v5623
+32552456v4254
+34465858v5452
+45466578v>>>>
+143859879845v
+445787698776v
+363787797965v
+465496798688v
+456467998645v
+122468686556v
+254654888773v
+432267465553v
+```
+
+In the above example, an ultra crucible would incur the minimum possible heat loss of **`94`**.
+
+Here's another example:
+
+```
+111111111111
+999999999991
+999999999991
+999999999991
+999999999991
+```
+
+Sadly, an ultra crucible would need to take an unfortunate path like this one:
+
+```
+1>>>>>>>1111
+9999999v9991
+9999999v9991
+9999999v9991
+9999999v>>>>
+```
+
+This route causes the ultra crucible to incur the minimum possible heat loss of **`71`**.
+
+Directing the **ultra crucible** from the lava pool to the machine parts factory, **what is the least heat loss it can incur?**

2023/Day_17/part_1.js

@@ -1,19 +1,36 @@
 "use strict";
 
+/* eslint-disable one-var */
+
 const fs = require("node:fs");
 const path = require("node:path");
 const { performance } = require("node:perf_hooks");
 
-const INPUT = String(fs.readFileSync(path.join(__dirname, "input.txt"))).trim().split("\n");
+const INPUT = String(fs.readFileSync(path.join(__dirname, "input.txt"))).trim().split("\n").map(l => l.split("").map(Number));
 
 const pStart = performance.now();
 
-//
-// YOUR CODE HERE
-//
-const result = "...";
+let res = 0;
+const q = [{ c: 0, row: 0, col: 0, dR: 0, dC: 0, m: 0 }], seen = new Set();
+while (q.length){ // @ts-ignore
+    const { c, row, col, dR, dC, m } = q.sort((p, n) => n.c - p.c).pop();
+    (row === (INPUT.length - 1) && col === (INPUT[0].length - 1) && m >= 1) && (res = c);
+    if (res !== 0) break;
+
+    if (seen.has(JSON.stringify([row, col, dR, dC, m]))) continue;
+    seen.add(JSON.stringify([row, col, dR, dC, m]));
+
+    ((m < 3 && !(dR === 0 && dC === 0))
+        && (row + dR >= 0 && row + dR < INPUT.length && col + dC >= 0 && col + dC < INPUT[0].length)
+        && q.push( { c: c + INPUT[row + dR][col + dC], row: row + dR, col: col + dC, dR, dC, m: m + 1 }) || 1)
+    && ((m >= 1 || (dR === 0 && dC === 0)) && [[0, 1], [1, 0], [0, -1], [-1, 0]].forEach(([nDR, nDC]) => (
+        (JSON.stringify([nDR, nDC]) !== JSON.stringify([dR, dC])) && (JSON.stringify([nDR, nDC]) !== JSON.stringify([-dR, -dC])))
+        && (row + nDR >= 0 && row + nDR < INPUT.length && col + nDC >= 0 && col + nDC < INPUT[0].length)
+        && q.push({ c: c + INPUT[row + nDR][col + nDC], row: row + nDR, col: col + nDC, dR: nDR, dC: nDC, m: 1 }),
+    ));
+}
 
 const pEnd = performance.now();
 
-console.log("<DESCRIPTION>: " + result);
+console.log("LEAST HEAT LOSS: " + res);
 console.log(pEnd - pStart);

2023/Day_17/part_2.js

@@ -1,19 +1,36 @@
 "use strict";
 
+/* eslint-disable one-var */
+
 const fs = require("node:fs");
 const path = require("node:path");
 const { performance } = require("node:perf_hooks");
 
-const INPUT = String(fs.readFileSync(path.join(__dirname, "input.txt"))).trim().split("\n");
+const INPUT = String(fs.readFileSync(path.join(__dirname, "input.txt"))).trim().split("\n").map(l => l.split("").map(Number));
 
 const pStart = performance.now();
 
-//
-// YOUR CODE HERE
-//
-const result = "...";
+let res = 0;
+const q = [{ c: 0, row: 0, col: 0, dR: 0, dC: 0, m: 0 }], seen = new Set();
+while (q.length){ // @ts-ignore
+    const { c, row, col, dR, dC, m } = q.sort((p, n) => n.c - p.c).pop();
+    (row === (INPUT.length - 1) && col === (INPUT[0].length - 1) && m >= 4) && (res = c);
+    if (res !== 0) break;
+
+    if (seen.has(JSON.stringify([row, col, dR, dC, m]))) continue;
+    seen.add(JSON.stringify([row, col, dR, dC, m]));
+
+    ((m < 10 && !(dR === 0 && dC === 0))
+        && (row + dR >= 0 && row + dR < INPUT.length && col + dC >= 0 && col + dC < INPUT[0].length)
+        && q.push( { c: c + INPUT[row + dR][col + dC], row: row + dR, col: col + dC, dR, dC, m: m + 1 }) || 1)
+    && ((m >= 4 || (dR === 0 && dC === 0)) && [[0, 1], [1, 0], [0, -1], [-1, 0]].forEach(([nDR, nDC]) => (
+        (JSON.stringify([nDR, nDC]) !== JSON.stringify([dR, dC])) && (JSON.stringify([nDR, nDC]) !== JSON.stringify([-dR, -dC])))
+        && (row + nDR >= 0 && row + nDR < INPUT.length && col + nDC >= 0 && col + nDC < INPUT[0].length)
+        && q.push({ c: c + INPUT[row + nDR][col + nDC], row: row + nDR, col: col + nDC, dR: nDR, dC: nDC, m: 1 }),
+    ));
+}
 
 const pEnd = performance.now();
 
-console.log("<DESCRIPTION>: " + result);
+console.log("NEW LEAST HEAT LOSS: " + res);
 console.log(pEnd - pStart);