AoC-2017-day3.js

function createMemorySpiralPart1() {
  map = [[5, 4, 3], [6, 1, 2], [7, 8, 9]];
  current = 9;
  mapSize = 4;
  row = 2;
  location = 2;
  while (current < input) {
    current++;
    position = { row, location };

    if (position.location === 0) {
      if (
        position.row === 0 &&
        map[position.row].length === mapSize &&
        map[position.row + 1].length === mapSize
      ) {
        map.push([]);
        mapSize++;
      }
      if (map[position.row].length < mapSize) {
        if (position.row === mapSize - 1) {
          map[position.row].push(current);
          location++;
        } else {
          map[position.row].unshift(current);
          location = 0;
        }
      } else {
        map[position.row + 1].unshift(current);
        row++;
        location = 0;
      }
    }

    if (position.location !== 0) {
      if (
        position.row == mapSize - 1 &&
        map[position.row].length === mapSize &&
        map[position.row - 1].length === mapSize
      ) {
        mapSize++;
      }
      if (position.row !== 0) {
        if (map[position.row].length < mapSize) {
          map[position.row].push(current);
          location++;
        } else {
          map[position.row - 1].push(current);
          row--;
          location++;
        }
      } else {
        map.unshift([current]);
        row = 0;
        location = 0;
      }
    }
  }
  return map;
}

function findInMap(find, map) {
  for (let r = 0; r < map.length; r++) {
    for (let i = 0; i < map[r].length; i++) {
      if (find === map[r][i]) {
        return {
          row: r,
          location: i
        };
      }
    }
  }
}

function createMemorySpiralPart2() {
  map = [[5, 4, 2], [10, 1, 1], [11, 23, 25]];
  lastValue = 25;
  mapSize = 4;
  nextValue = 0;
  while (lastValue < input) {
    position = findInMap(lastValue, map);
    if (position.location === 0) {
      if (
        position.row === 0 &&
        map[position.row].length === mapSize &&
        map[position.row + 1].length === mapSize
      ) {
        map.push([]);
        mapSize++;
      }
      if (map[position.row].length < mapSize) {
        if (position.row === mapSize - 1) {
          lastValue =
            map[position.row][position.location] +
            map[position.row - 1][position.location] +
            map[position.row - 1][position.location + 1] +
            map[position.row - 1][position.location + 2];
          map[position.row].push(lastValue);
        } else {
          offset = map[position.row + 1].length - map[position.row].length;
          lastValue =
            map[position.row][position.location] +
            map[position.row + 1][offset] +
            (offset - 1 >= 0 ? map[position.row + 1][offset - 1] : 0) +
            (offset - 2 >= 0 ? map[position.row + 1][offset - 2] : 0);
          map[position.row].unshift(lastValue);
        }
      } else {
        lastValue =
          map[position.row][position.location] +
          map[position.row][position.location + 1] +
          (position.row + 1 < mapSize - 1
            ? map[position.row + 1][position.location]
            : 0) +
          (position.row + 2 < mapSize - 1
            ? map[position.row + 2][position.location]
            : 0);
        map[position.row + 1].unshift(lastValue);
      }
    }
    if (position.location !== 0) {
      if (
        position.row == mapSize - 1 &&
        map[position.row].length === mapSize &&
        map[position.row - 1].length === mapSize
      ) {
        mapSize++;
      }
      if (position.row !== 0) {
        if (map[position.row].length < mapSize) {
          offset = map[position.row - 1].length - 1 - position.location;
          lastValue =
            map[position.row][position.location] +
            map[position.row - 1][position.location] +
            (offset > 0 ? map[position.row - 1][position.location + 1] : 0) +
            (offset > 1 ? map[position.row - 1][position.location + 2] : 0);

          map[position.row].push(lastValue);
        } else {
          lastValue =
            map[position.row][position.location] +
            map[position.row][position.location - 1] +
            map[position.row - 1][position.location - 1] +
            (position.row - 2 >= 0
              ? map[position.row - 2][position.location - 1]
              : 0);
          map[position.row - 1].push(lastValue);
        }
      } else {
        lastValue =
          map[position.row][position.location] +
          map[position.row][position.location - 1];
        map.unshift([lastValue]);
      }
    }
  }
  return lastValue;
}

function findInMap(find, map) {
  for (let r = 0; r < map.length; r++) {
    for (let i = 0; i < map[r].length; i++) {
      if (find === map[r][i]) {
        return {
          row: r,
          location: i
        };
      }
    }
  }
}

const input = 277678;

// Part 1
console.log("Part 1");
map = createMemorySpiralPart1();
start = findInMap(1, map);
end = findInMap(277678, map);
console.log(
  "Distance: " +
    Math.abs(start.row - end.row + start.location - end.location + "\n")
);

// Part 2
console.log("Part 2");
console.log("Next highest:", createMemorySpiralPart2());