2023 day 12 part 1

2023/day12-hot-springs/day12.jl

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+function parsespring(line)
+    return split(line)[1], map(x->parse(Int,x),
+                               split(split(line)[2], ","))
+end
+
+function issolution(str, lengths)
+    springs = split(strip(str, ['.']), '.', keepempty=false)
+    length(springs) == length(lengths) && all(map((spring,sprlen)->length(spring)==sprlen,
+                                                  springs, lengths))
+end
+
+function solvesprings(springs, lengths)
+    ndamage = count('?', springs)
+    solutions = Vector{AbstractString}()
+    for i in 0:2^ndamage-1
+        bit = 0
+        cand = map(springs) do ch
+            if ch == '?'
+                out = (i & 1<<bit != 0) ? '#' : '.'
+                bit += 1
+                out
+            else
+                ch
+            end
+        end
+        if issolution(String(cand), lengths)
+            push!(solutions, String(cand))
+        end
+    end
+    solutions
+end
+
+input = map(parsespring, eachline("input"))
+println("Part 1: ", sum(map(length, map(x->solvesprings(x[1],x[2]), input))))

2023/day12-hot-springs/example

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+???.### 1,1,3
+.??..??...?##. 1,1,3
+?#?#?#?#?#?#?#? 1,3,1,6
+????.#...#... 4,1,1
+????.######..#####. 1,6,5
+?###???????? 3,2,1