From 077485197b06b6bc76101c3049dae72450b20471 Mon Sep 17 00:00:00 2001 From: Maya Herrscher Date: Thu, 8 Dec 2022 15:18:08 +0100 Subject: [PATCH] Add solution for day 08 --- 2022/day08/challenge | 76 ++++++++++++++++++++++++++++++++++ 2022/day08/code.py | 60 +++++++++++++++++++++++++++ 2022/day08/example | 5 +++ 2022/day08/input | 99 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 240 insertions(+) create mode 100644 2022/day08/challenge create mode 100755 2022/day08/code.py create mode 100644 2022/day08/example create mode 100644 2022/day08/input diff --git a/2022/day08/challenge b/2022/day08/challenge new file mode 100644 index 0000000..a73097b --- /dev/null +++ b/2022/day08/challenge @@ -0,0 +1,76 @@ +--- Day 8: Treetop Tree House --- + +The expedition comes across a peculiar patch of tall trees all planted carefully in a grid. The Elves explain that a previous expedition planted these trees as a reforestation effort. Now, they're curious if this would be a good location for a tree house. + +First, determine whether there is enough tree cover here to keep a tree house hidden. To do this, you need to count the number of trees that are visible from outside the grid when looking directly along a row or column. + +The Elves have already launched a quadcopter to generate a map with the height of each tree (your puzzle input). For example: + +30373 +25512 +65332 +33549 +35390 + +Each tree is represented as a single digit whose value is its height, where 0 is the shortest and 9 is the tallest. + +A tree is visible if all of the other trees between it and an edge of the grid are shorter than it. Only consider trees in the same row or column; that is, only look up, down, left, or right from any given tree. + +All of the trees around the edge of the grid are visible - since they are already on the edge, there are no trees to block the view. In this example, that only leaves the interior nine trees to consider: + + The top-left 5 is visible from the left and top. (It isn't visible from the right or bottom since other trees of height 5 are in the way.) + The top-middle 5 is visible from the top and right. + The top-right 1 is not visible from any direction; for it to be visible, there would need to only be trees of height 0 between it and an edge. + The left-middle 5 is visible, but only from the right. + The center 3 is not visible from any direction; for it to be visible, there would need to be only trees of at most height 2 between it and an edge. + The right-middle 3 is visible from the right. + In the bottom row, the middle 5 is visible, but the 3 and 4 are not. + +With 16 trees visible on the edge and another 5 visible in the interior, a total of 21 trees are visible in this arrangement. + +Consider your map; how many trees are visible from outside the grid? + +Your puzzle answer was 1823. +--- Part Two --- + +Content with the amount of tree cover available, the Elves just need to know the best spot to build their tree house: they would like to be able to see a lot of trees. + +To measure the viewing distance from a given tree, look up, down, left, and right from that tree; stop if you reach an edge or at the first tree that is the same height or taller than the tree under consideration. (If a tree is right on the edge, at least one of its viewing distances will be zero.) + +The Elves don't care about distant trees taller than those found by the rules above; the proposed tree house has large eaves to keep it dry, so they wouldn't be able to see higher than the tree house anyway. + +In the example above, consider the middle 5 in the second row: + +30373 +25512 +65332 +33549 +35390 + + Looking up, its view is not blocked; it can see 1 tree (of height 3). + Looking left, its view is blocked immediately; it can see only 1 tree (of height 5, right next to it). + Looking right, its view is not blocked; it can see 2 trees. + Looking down, its view is blocked eventually; it can see 2 trees (one of height 3, then the tree of height 5 that blocks its view). + +A tree's scenic score is found by multiplying together its viewing distance in each of the four directions. For this tree, this is 4 (found by multiplying 1 * 1 * 2 * 2). + +However, you can do even better: consider the tree of height 5 in the middle of the fourth row: + +30373 +25512 +65332 +33549 +35390 + + Looking up, its view is blocked at 2 trees (by another tree with a height of 5). + Looking left, its view is not blocked; it can see 2 trees. + Looking down, its view is also not blocked; it can see 1 tree. + Looking right, its view is blocked at 2 trees (by a massive tree of height 9). + +This tree's scenic score is 8 (2 * 2 * 1 * 2); this is the ideal spot for the tree house. + +Consider each tree on your map. What is the highest scenic score possible for any tree? + +Your puzzle answer was 211680. + +Both parts of this puzzle are complete! They provide two gold stars: ** diff --git a/2022/day08/code.py b/2022/day08/code.py new file mode 100755 index 0000000..5b53f28 --- /dev/null +++ b/2022/day08/code.py @@ -0,0 +1,60 @@ +#!/usr/bin/env python3 + +import sys + + +def visible(t,x,y): + if x == 0 or y == 0 or x == (len(t[0]) - 1) or y == (len(t) - 1): + return 1 + h = t[y][x] + v = 1 + for r in [(0,x),(x+1,len(t[y]))]: # left, right + for i in range(*r): + if h <= t[y][i]: v = 0 + if v == 1: return v + else: v = 1 + for r in [(0,y),(y+1,len(t))]: # up, down + for i in range(*r): + if h <= t[i][x]: v = 0 + if v == 1: return v + else: v = 1 + return 0 + +def scenic(t,x,y): + if x == 0 or y == 0 or x == (len(t[0]) - 1) or y == (len(t) - 1): + return 0 + h = t[y][x] + score = 1 + cur = 0 + for r in [(x-1,-1,-1),(x+1,len(t[y]))]: # left, right + for i in range(*r): + cur = cur + 1 + if h <= t[y][i]: break + score = score * cur + cur = 0 + for r in [(y-1,-1,-1),(y+1,len(t))]: # up, down + for i in range(*r): + cur = cur + 1 + if h <= t[i][x]: break + score = score * cur + cur = 0 + return score + +if __name__ == '__main__': + trees = [[int(l) for l in list(line.strip('\n'))] for line in open(sys.argv[1])] + vis = 0 + scene = 0 + for i in range(len(trees)): + for j in range(len(trees[i])): + vis = vis + visible(trees,j,i) + sc_score = scenic(trees,j,i) + if sc_score > scene: scene = sc_score + + # challenge 1 + res1 = str(vis) + print("challenge 1:" + "\n" + res1 + "\n") + + # challenge 2 + res2 = str(scene) + print("challenge 2:" + "\n" + res2 + "\n") + diff --git a/2022/day08/example b/2022/day08/example new file mode 100644 index 0000000..16d6fbd --- /dev/null +++ b/2022/day08/example @@ -0,0 +1,5 @@ +30373 +25512 +65332 +33549 +35390 diff --git a/2022/day08/input b/2022/day08/input new file mode 100644 index 0000000..b24a68f --- /dev/null +++ b/2022/day08/input @@ -0,0 +1,99 @@ +202210010310302121322210423201220000314024242432211425434422230130411300321324302223011311211020120 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