「🎉」 init(2025): day 1

2024/day10/.envrc

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+use flake

2024/day10/flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1733730953,
+        "narHash": "sha256-dlK7n82FEyZlHH7BFHQAM5tua+lQO1Iv7aAtglc1O5s=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7109b680d161993918b0a126f38bc39763e5a709",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-24.05",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

2024/day10/flake.nix

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+{
+  description = "a minimal test development environment for ruby";
+
+  inputs = {
+
+    nixpkgs = {
+      url = "nixpkgs/nixos-24.05";
+      flake = false;
+	};
+
+  };
+
+  outputs = inputs@{ nixpkgs, ... }:
+	{
+    devShell = {
+      x86_64-linux = let
+        pkgs = import nixpkgs { system = "x86_64-linux"; };
+	  in pkgs.mkShell {
+        packages = with pkgs; [
+          gcc ruby
+        ];
+        shellHook = ''
+          export CC=gcc
+          echo -e "\x1B[0;33mentering ruby minimalist test development environment...\x1B[0m"
+        '';
+      };
+    };
+  };
+}

2024/day10/part1.rb

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+require 'set'
+
+def find_trailheads(grid)
+  trailheads = []
+  grid.each_with_index do |row, y|
+    row.each_char.with_index do |height, x|
+      trailheads << [x, y] if height == '0'
+    end
+  end
+  trailheads
+end
+
+def find_path(grid, x, y, visited)
+  score = 0
+
+  visited.add([x, y])
+
+  return 1 if grid[y][x] == '9'
+
+  [[-1, 0], [1, 0], [0, -1], [0, 1]].each do |x_dir, y_dir|
+    nx, ny = x + x_dir, y + y_dir
+    next unless ny.between?(0, grid.size - 1) && nx.between?(0, grid[0].length - 1)
+    next if visited.include?([nx, ny])
+    
+    if grid[ny][nx].to_i == grid[y][x].to_i + 1
+      score += find_path(grid, nx, ny, visited)
+    end
+  end
+  score
+end
+
+
+
+if File.exists?("input.txt")
+  file = File.open("input.txt")
+  file_data = file.read
+  file.close
+else
+  file_data = "89010123\n78121874\n87430965\n96549874\n45678903\n32019012\n01329801\n10456732"
+end
+
+grid = file_data.split("\n")
+
+trailheads = find_trailheads(grid)
+result = 0
+
+trailheads.each do |trailhead|
+  result += find_path(grid, trailhead[0], trailhead[1], Set.new)
+  #puts result
+end
+
+puts "result : #{result}"

2024/day10/part2.rb

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+require 'set'
+
+def find_trailheads(grid)
+  trailheads = []
+  grid.each_with_index do |row, y|
+    row.each_char.with_index do |height, x|
+      trailheads << [x, y] if height == '0'
+    end
+  end
+  trailheads
+end
+
+def find_path(grid, x, y, visited)
+  score = 0
+
+  return 1 if grid[y][x] == '9'
+
+  visited.add([x, y])
+
+  [[-1, 0], [1, 0], [0, -1], [0, 1]].each do |x_dir, y_dir|
+    nx, ny = x + x_dir, y + y_dir
+    next unless ny.between?(0, grid.size - 1) && nx.between?(0, grid[0].length - 1)
+    next if visited.include?([nx, ny])
+    
+    if grid[ny][nx].to_i == grid[y][x].to_i + 1
+      score += find_path(grid, nx, ny, visited)
+    end
+  end
+
+  visited.delete([x, y])
+  score
+end
+
+
+
+if File.exists?("input.txt")
+  file = File.open("input.txt")
+  file_data = file.read
+  file.close
+else
+  file_data = "89010123\n78121874\n87430965\n96549874\n45678903\n32019012\n01329801\n10456732"
+end
+
+grid = file_data.split("\n")
+
+trailheads = find_trailheads(grid)
+result = 0
+
+trailheads.each do |trailhead|
+  result += find_path(grid, trailhead[0], trailhead[1], Set.new)
+  #puts result
+end
+
+puts "result : #{result}"