Solution to Day 2 in Julia

src/Year_2025/Julia/Day02/aoc_02.jl

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+#!/usr/bin/env -S julia --project
+module AdventOfCodeDayXX
+    function parse_part1(filename::String)
+        ranges = split(read(filename, String), ",")
+        return ranges
+    end
+
+    function part1(filename::String)
+        ranges = parse_part1(filename)
+        invalid::Int = 0
+        for r in ranges
+            id1, id2 = split(r, "-")
+            start_id = parse(Int, strip(id1))
+            end_id = parse(Int, strip(id2))
+            for value in start_id:end_id
+                s = collect(string(value))
+                half = length(s) ÷ 2
+                if s[1:half] == s[half + 1:end]
+                    invalid += value
+                end
+            end
+        end
+        return invalid
+    end
+
+   function part2(filename::String)
+        ranges = parse_part1(filename)
+        invalid::Int = 0
+        for r in ranges
+            id1, id2 = split(r, "-")
+            start_id = parse(Int, strip(id1))
+            end_id = parse(Int, strip(id2))
+            for value in start_id:end_id
+                s = collect(string(value))
+                for cutoff in 1:(length(s) ÷ 2)
+                    left = s[1:cutoff]
+                    right_start = cutoff + 1
+                    repeating = true
+                    while right_start <= length(s)
+                        right_end = right_start + cutoff - 1
+                        if right_end > length(s) || s[right_start:right_end] != left
+                            repeating = false
+                            break
+                        end
+                        right_start += cutoff
+                    end
+                    if repeating && length(s) % cutoff == 0
+                        invalid += value
+                        break
+                    end
+                end
+            end
+        end
+        return invalid
+    end
+
+    function main()
+        demo_p1 = part1("demo.txt")
+        input_p1 = part1("input.txt")
+        demo_p2 = part2("demo.txt")
+        input_p2 = part2("input.txt")
+
+        println("Advent of Code — Day 02")
+        println("="^23)
+        println("Demo Results:")
+        println("  Part 1: ", demo_p1)
+        println("  Part 2: ", demo_p2)
+        println()
+        println("Input Results:")
+        println("  Part 1: ", input_p1)
+        println("  Part 2: ", input_p2)
+        println("="^23)
+    end
+
+    function __init__()
+        if abspath(PROGRAM_FILE) == @__FILE__
+            main()
+        end
+    end
+end

src/Year_2025/Julia/Day02/demo.txt

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+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124

src/Year_2025/Julia/Day02/input.txt

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+492410748-492568208,246-390,49-90,16-33,142410-276301,54304-107961,12792-24543,3434259704-3434457648,848156-886303,152-223,1303-1870,8400386-8519049,89742532-89811632,535853-567216,6608885-6724046,1985013826-1985207678,585591-731454,1-13,12067202-12233567,6533-10235,6259999-6321337,908315-972306,831-1296,406-824,769293-785465,3862-5652,26439-45395,95-136,747698990-747770821,984992-1022864,34-47,360832-469125,277865-333851,2281-3344,2841977-2953689,29330524-29523460