Day 10 possibly complete

but way to resource intensive

2020/day10/main.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	fmt.Println("# Day 10")
+	inp := h.StdinToIntSlice()
+	sort.Ints(inp)
+	jumps := part1(inp)
+	fmt.Println("## Part 1")
+	fmt.Println(jumps[1] * jumps[3])
+
+	fmt.Println("## Part 2")
+	fmt.Println(part2(inp))
+}
+
+func part1(inp []int) map[int]int {
+	jumps := make(map[int]int)
+	var curr int
+	var used []int
+	wrk := make([]int, len(inp))
+	copy(wrk, inp)
+	for len(used) < len(inp) {
+		var next int
+		for i := range wrk {
+			if i == 0 {
+				next = wrk[i]
+			} else {
+				diff := wrk[i] - curr
+				if diff > 0 && diff < next-curr {
+					next = wrk[i]
+				}
+			}
+		}
+		jumps[next-curr]++
+		curr = next
+		used = append(used, curr)
+		var nextList []int
+		for i := range wrk {
+			if wrk[i] != curr {
+				nextList = append(nextList, wrk[i])
+			}
+		}
+		wrk = make([]int, len(nextList))
+		copy(wrk, nextList)
+	}
+	jumps[3]++
+	return jumps
+}
+
+var prevs map[int][]int
+var psbs map[int][][]int
+
+func part2(inp []int) int {
+	psbs = make(map[int][][]int)
+	psbs[0] = [][]int{{0}}
+	prevs = make(map[int][]int)
+	var phone int
+	for i := range inp {
+		if inp[i] > phone {
+			phone = inp[i]
+		}
+	}
+	// Add the outlet
+	inp = append(inp, 0)
+	// Add the phone
+	phone = phone + 3
+	inp = append(inp, phone)
+	for i := range inp {
+		prevs[inp[i]] = findPrevPoss(inp[i], inp)
+	}
+
+	total := len(findConfigs(phone))
+	return total
+}
+
+func findConfigs(curr int) [][]int {
+	if p, ok := psbs[curr]; ok {
+		return p
+	} else {
+		var ret [][]int
+		for _, v := range prevs[curr] {
+			rec := findConfigs(v)
+			if len(rec) > 0 {
+				for _, rv := range rec {
+					ret = append(ret, append([]int{curr}, rv...))
+				}
+			} else {
+				ret = [][]int{{curr}}
+			}
+		}
+		psbs[curr] = ret
+		return ret
+	}
+}
+
+// Find the options immediately preceeding curr
+func findPrevPoss(curr int, inp []int) []int {
+	if curr == 0 {
+		return []int{}
+	}
+	var next []int
+	for i := range inp {
+		if inp[i] >= curr {
+			continue
+		}
+		if curr-inp[i] <= 3 {
+			next = append(next, inp[i])
+		}
+	}
+	return next
+}