12 was a pain

2022/12/index.js

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+const fs = require('fs/promises');
+
+const sum = (arr) => arr.reduce((total, num) => total+num, 0);
+const arrayOfLength = n => Array.from(Array(n).keys()).map(() => {});
+
+const main = async () => {
+  const input = (await fs.readFile("./input.txt", 'utf8')).split("\n").map(x => x.split("").map(x => x.charCodeAt(0)));
+
+  const maxY = input.length;
+  const maxX = input[0].length;
+  let minPath = Infinity;
+
+  const visited = arrayOfLength(maxY).map(_ => arrayOfLength(maxX));
+  const shortestPaths = arrayOfLength(maxY).map(_ => arrayOfLength(maxX).map(_ => Infinity));
+
+  const start = input.reduce((found, row, i) => {
+    if(found) return found;
+
+    const j = row.indexOf(83);
+    if(j !== -1) {
+      return [j, i];
+    }
+
+  }, undefined);
+
+  // Added this so I could watch an algorithm to see how quickly it was
+  // progressing.  The final algorithm ended up being so quick that this can't
+  // even render it properly
+
+  let nextPrint = 0;
+
+  const print = () => {
+    if(Date.now() > nextPrint) {
+      process.stdout.write('\u001b[2J');
+      process.stdout.write('\u001b[;H');
+      console.log(visited.map(row => row.map(x => x ? "X": ".").join("")).join("\n"));
+      console.log("\n\n\n")
+      console.log("Paths found: ", minPath);
+      nextPrint = Date.now() + 10;
+    }
+  };
+
+  const canVisit = ([fx,fy], [tx,ty]) => {
+    // Don't go off the map
+    if(Math.min(tx, ty) < 0 || tx >= maxX  || ty >= maxY) {
+      return false;
+    }
+
+    // Don't visit squares we've already visited.
+    if(visited[ty][tx]) {
+      return false;
+    }
+
+    // S = a and E = z
+    let fz = input[fy][fx] === 83 ? 97 : input[fy][fx];
+    let tz = input[ty][tx] === 69 ? 122 : input[ty][tx];
+
+    // No climbing gear allowed
+    return tz <= fz + 1;
+  }
+
+  const explore = (visited, loc, stepCount) => {
+    const [x, y] = loc;
+
+    //If we've already found a solution that is shorter than the path so far,
+    //there is no reason to continue
+    if(stepCount >= minPath) {
+      return false;
+    }
+
+    //If we've alreayd found a shorter path to this square then there is no
+    //sense in trying a longer path.  This ended up shortening the time by
+    //alot.
+    if(stepCount >= shortestPaths[y][x]) {
+      return false;
+    } else {
+      shortestPaths[y][x] = stepCount;
+    }
+
+    //Print the rendering that is actually usesless once I found the solution
+    print();
+    if(input[y][x] === 69) {
+      minPath = Math.min(minPath, stepCount);
+      return true;
+    }
+
+    //Track what has been visited on the current path
+    visited[y][x] = true
+
+    const nextSteps = [[x + 1, y],[x, y + 1],[x, y - 1],[x - 1, y]];
+
+    //Try each direction
+    const found = nextSteps.map(nextStep => {
+      if(canVisit(loc, nextStep)) {
+        return explore(visited, nextStep, stepCount + 1);
+      }
+      return false
+    });
+
+    //Mark this one as no longer visited so we can try it again on another path.
+    visited[y][x] = false;
+    return false;
+  }
+
+  console.log(start);
+
+  //start exploring
+  explore(visited, start, 0);
+
+  console.log(minPath);
+
+}
+
+main();

2022/12/index2.js

@@ -0,0 +1,127 @@
+const fs = require('fs/promises');
+
+const sum = (arr) => arr.reduce((total, num) => total+num, 0);
+const arrayOfLength = n => Array.from(Array(n).keys()).map(() => {});
+
+const main = async () => {
+  const input = (await fs.readFile("./input.txt", 'utf8')).split("\n").map(x => x.split("").map(x => x.charCodeAt(0)));
+  const start = input.reduce((found, row, i) => {
+    if(found) return found;
+
+    const j = row.indexOf(83);
+    if(j !== -1) {
+      return [j, i];
+    }
+
+  }, undefined);
+
+  let minPath = Infinity;
+  const maxY = input.length;
+  const maxX = input[0].length;
+
+  //Wrapped most of the context into a function that could be called over and
+  //over to try again from differnt points
+  const exploreMapFrom = (start) => {
+
+    const visited = arrayOfLength(maxY).map(_ => arrayOfLength(maxX));
+    const shortestPaths = arrayOfLength(maxY).map(_ => arrayOfLength(maxX).map(_ => Infinity));
+
+
+    // Added this print function so I could watch an algorithm to see how
+    // quickly it was progressing.  The final algorithm ended up being so quick
+    // that this can't even render it properly
+
+    let nextPrint = 0;
+
+    const print = () => {
+      if(Date.now() > nextPrint) {
+        process.stdout.write('\u001b[2J');
+        process.stdout.write('\u001b[;H');
+        console.log(visited.map(row => row.map(x => x ? "X": ".").join("")).join("\n"));
+        console.log("\n\n\n")
+        console.log("Paths found: ", minPath);
+        nextPrint = Date.now() + 10;
+      }
+    };
+
+    const canVisit = ([fx,fy], [tx,ty]) => {
+      // Don't go off the map
+      if(Math.min(tx, ty) < 0 || tx >= maxX  || ty >= maxY) {
+        return false;
+      }
+
+      // Don't visit squares we've already visited.
+      if(visited[ty][tx]) {
+        return false;
+      }
+
+      // S = a and E = z
+      let fz = input[fy][fx] === 83 ? 97 : input[fy][fx];
+      let tz = input[ty][tx] === 69 ? 122 : input[ty][tx];
+
+      // No climbing gear allowed
+      return tz <= fz + 1;
+    }
+
+    const explore = (visited, loc, stepCount) => {
+      const [x, y] = loc;
+
+      //If we've already found a solution that is shorter than the path so far,
+      //there is no reason to continue
+      if(stepCount >= minPath) {
+        return false;
+      }
+
+      //If we've alreayd found a shorter path to this square then there is no
+      //sense in trying a longer path.  This ended up shortening the time by
+      //alot.
+      if(stepCount >= shortestPaths[y][x]) {
+        return false;
+      } else {
+        shortestPaths[y][x] = stepCount;
+      }
+
+      //Print the rendering that is actually usesless once I found the solution
+      print();
+      if(input[y][x] === 69) {
+        minPath = Math.min(minPath, stepCount);
+        return true;
+      }
+
+      //Track what has been visited on the current path
+      visited[y][x] = true
+
+      const nextSteps = [[x + 1, y],[x, y + 1],[x, y - 1],[x - 1, y]];
+
+      //Try each direction
+      const found = nextSteps.map(nextStep => {
+        if(canVisit(loc, nextStep)) {
+          return explore(visited, nextStep, stepCount + 1);
+        }
+        return false
+      });
+
+      //Mark this one as no longer visited so we can try it again on another path.
+      visited[y][x] = false;
+      return false;
+    }
+
+    //start exploring
+    explore(visited, start, 0);
+  }
+  // Try starting from "S"
+  exploreMapFrom(start);
+
+  //Try starting from all the "a"s
+  for(let x = 0; x < maxX; ++x) {
+    for(let y = 0; y < maxY; ++y) {
+      if(input[y][x] === 97) {
+        exploreMapFrom([x, y]);
+      }
+    }
+  }
+
+  console.log(minPath);
+}
+
+main();

2022/12/input.txt

@@ -0,0 +1,41 @@
+abaaaaaccccccccccccccccccaaaaaaaaaaaaaccccaaaaaaaccccccccccccccccccccccccccccaaaaaa
+abaaaaaaccaaaacccccccccccaaaaaaaaacaaaacaaaaaaaaaacccccccccccccccccccccccccccaaaaaa
+abaaaaaacaaaaaccccccccccaaaaaaaaaaaaaaacaaaaaaaaaacccccccccccccaacccccccccccccaaaaa
+abaaaaaacaaaaaacccccccccaaaaaaaaaaaaaaccaaacaaaccccccccccccccccaacccccccccccccccaaa
+abccaaaccaaaaaacccaaaaccaaaaaaaaaaaaaccccaacaaacccccccccaacaccccacccccccccccccccaaa
+abcccccccaaaaaccccaaaacccccaaaaacccaaaccaaaaaaccccccccccaaaaccccccccccccccccccccaac
+abcccccccccaaaccccaaaacccccaaaaacccccccccaaaaaccccccccccklllllccccccccccccccccccccc
+abcccccccccccccccccaaccccccccaaccccccccaaaaaaaccccccccckklllllllcccccddccccaacccccc
+abaccccccccccccccccccccccccccaaccccccccaaaaaaaaccccccckkkklslllllcccddddddaaacccccc
+abacccccccccccccccccccccccccccccccaaaccaaaaaaaaccccccckkkssssslllllcddddddddacccccc
+abaccccccccccccccccccccccccccccccccaaaaccaaacaccccccckkksssssssslllmmmmmdddddaacccc
+abcccccccccccccccaaacccccccccccccaaaaaaccaacccccccccckkkssssusssslmmmmmmmdddddacccc
+abcccccccaaccccaaaaacccccccccccccaaaaaccccccaaaaaccckkkrssuuuussssqmmmmmmmmdddccccc
+abcccccccaaccccaaaaaacccccccaaccccaaaaacccccaaaaacckkkkrruuuuuussqqqqqqmmmmdddccccc
+abccccaaaaaaaacaaaaaacccccccaaaaccaaccaccccaaaaaacjkkkrrruuuxuuusqqqqqqqmmmmeeccccc
+abcaaaaaaaaaaacaaaaaccccccaaaaaacccccaaccccaaaaajjjjrrrrruuuxxuvvvvvvvqqqmmmeeccccc
+abcaacccaaaaccccaaaaaaacccaaaaacccacaaaccccaaaajjjjrrrrruuuxxxxvvvvvvvqqqmmeeeccccc
+abaaaaccaaaaacccccccaaaccccaaaaacaaaaaaaacccaajjjjrrrrtuuuuxxxyvyyyvvvqqqnneeeccccc
+abaaaaaaaaaaacccaaaaaaaccccaacaacaaaaaaaacccccjjjrrrttttuxxxxxyyyyyvvvqqnnneeeccccc
+abaaaaaaaccaacccaaaaaaaaacccccccccaaaaaaccccccjjjrrrtttxxxxxxxyyyyyvvvqqnnneeeccccc
+SbaaaaaacccccccccaaaaaaaaaccccccccaaaaacccccccjjjrrrtttxxxEzzzzyyyvvrrrnnneeecccccc
+abaaaaacccccccccccaaaaaaacccccccccaaaaaaccccccjjjqqqtttxxxxxyyyyyvvvrrrnnneeecccccc
+abaaacccccccccccaaaaaaaccaaccccccccccaaccaaaaajjjqqqttttxxxxyyyyyyvvrrrnnneeecccccc
+abaaacccccccccccaaaaaaaccaaacaaacccccccccaaaaajjjjqqqtttttxxyywyyyywvrrnnnfeecccccc
+abcaaacccccccaaaaaaaaaaacaaaaaaaccccccccaaaaaaciiiiqqqqtttxwyywwyywwwrrrnnfffcccccc
+abcccccccccccaaaaaaaaaaccaaaaaacccccccccaaaaaacciiiiqqqqttwwywwwwwwwwrrrnnfffcccccc
+abccccccccccccaaaaaacccaaaaaaaacccccccccaaaaaaccciiiiqqqttwwwwwswwwwrrrrnnfffcccccc
+abccccccccccccaaaaaacccaaaaaaaaacccccccccaaacccccciiiqqqtswwwwssssrrrrrroofffcccccc
+abccccccaaaaacaaaaaacccaaaaaaaaaaccccccccccccccccciiiqqqssswsssssssrrrrooofffaccccc
+abccccccaaaaacaaccaaccccccaaacaaacccccccccccccccccciiiqqssssssspoorrrooooofffaacccc
+abcccccaaaaaacccccccccccccaaacccccccccccccccccccccciiiqppssssspppooooooooffffaacccc
+abcccccaaaaaacccccccccccccaacccccccccccccccccccccccciipppppppppppoooooooffffaaccccc
+abcccccaaaaaaccccccccccccccccccccccccccccccccccccccciihppppppppgggggggggfffaaaccccc
+abccccccaaacccccccccccccccccccccccaccccccccccccccccchhhhpppppphggggggggggfaaaaccccc
+abaaaccccccccccccccccccccccaccccaaacccccccccccccccccchhhhhhhhhhgggggggggcaacccccccc
+abaaccaaaccaccccccccccccccaaacccaaacaacccaaaaacccccccchhhhhhhhhgaaccccccccccccccccc
+abaaacaaacaacccccccccaaaccaaaacaaaaaaaaccaaaaaccccccccchhhhhhaaaaacccccccccccccccca
+abaaaccaaaaaccccccccccaaacaaaaaaaacaaaaccaaaaaaccccccccccaaacccaaaacccccccccccaccca
+abcccaaaaaaccccccccccaaaaaaaaaaaaacaaaaccaaaaaaccccccccccaaaccccaaaccccccccccaaaaaa
+abcccaaaaaaaacccccccaaaaaaaaaaaaaaaaaccccaaaaaacccccccccccccccccccccccccccccccaaaaa
+abcccaacaaaaaccccccaaaaaaaaaaaaaaaaaaacccccaacccccccccccccccccccccccccccccccccaaaaa