From a28a6fd163f85bd842b3bdef76236b78f6a8babf Mon Sep 17 00:00:00 2001
From: Brian Buller <brian@bullercodeworks.com>
Date: Tue, 3 Dec 2019 09:25:11 -0600
Subject: [PATCH] Super-Optimized 2019 Day 2

---
 2019/day02/input2  |  1 +
 2019/day02/input3  |  1 +
 2019/day02/main.go | 36 +++++++++++++++++++++++++-----------
 3 files changed, 27 insertions(+), 11 deletions(-)
 create mode 100644 2019/day02/input2
 create mode 100644 2019/day02/input3

diff --git a/2019/day02/input2 b/2019/day02/input2
new file mode 100644
index 0000000..9b4335a
--- /dev/null
+++ b/2019/day02/input2
@@ -0,0 +1 @@
+1,0,0,3,1,1,2,3,1,3,4,3,1,5,0,3,2,10,1,19,1,19,5,23,1,23,9,27,2,27,6,31,1,31,6,35,2,35,9,39,1,6,39,43,2,10,43,47,1,47,9,51,1,51,6,55,1,55,6,59,2,59,10,63,1,6,63,67,2,6,67,71,1,71,5,75,2,13,75,79,1,10,79,83,1,5,83,87,2,87,10,91,1,5,91,95,2,95,6,99,1,99,6,103,2,103,6,107,2,107,9,111,1,111,5,115,1,115,6,119,2,6,119,123,1,5,123,127,1,127,13,131,1,2,131,135,1,135,10,0,99,2,14,0,0
diff --git a/2019/day02/input3 b/2019/day02/input3
new file mode 100644
index 0000000..5233427
--- /dev/null
+++ b/2019/day02/input3
@@ -0,0 +1 @@
+1,0,0,3,1,1,2,3,1,3,4,3,1,5,0,3,2,1,10,19,1,6,19,23,1,13,23,27,1,6,27,31,1,31,10,35,1,35,6,39,1,39,13,43,2,10,43,47,1,47,6,51,2,6,51,55,1,5,55,59,2,13,59,63,2,63,9,67,1,5,67,71,2,13,71,75,1,75,5,79,1,10,79,83,2,6,83,87,2,13,87,91,1,9,91,95,1,9,95,99,2,99,9,103,1,5,103,107,2,9,107,111,1,5,111,115,1,115,2,119,1,9,119,0,99,2,0,14,0
diff --git a/2019/day02/main.go b/2019/day02/main.go
index 7788ddd..69cb2ff 100644
--- a/2019/day02/main.go
+++ b/2019/day02/main.go
@@ -18,7 +18,6 @@ func main() {
 	for _, v := range strings.FieldsFunc(inp, f) {
 		prog = append(prog, Atoi(v))
 	}
-	//part1(prog)
 	part2(prog)
 }
 
@@ -36,6 +35,31 @@ func part1(prog []int) {
 	}
 }
 
+func part2(prog []int) {
+	runProg := func(n, v int, prog []int) int {
+		progcpy := make([]int, len(prog))
+		copy(progcpy, prog)
+		progcpy[1] = n
+		progcpy[2] = v
+		for i := 0; i < len(progcpy); i += 4 {
+			switch progcpy[i] {
+			case 1:
+				progcpy[progcpy[i+3]] = add(progcpy[i+1], progcpy[i+2], progcpy)
+			case 2:
+				progcpy[progcpy[i+3]] = mult(progcpy[i+1], progcpy[i+2], progcpy)
+			case 99:
+				i = len(progcpy)
+			}
+		}
+		return progcpy[0]
+	}
+	target := 19690720
+	zeroVal := runProg(0, 0, prog)
+	nDiff := runProg(1, 0, prog) - zeroVal
+	vDiff := runProg(0, 1, prog) - zeroVal
+	fmt.Println(((target - zeroVal) / nDiff), ((target%nDiff)-(zeroVal%nDiff))/vDiff)
+}
+
 func slowestPart2(prog []int) {
 	for n := 0; n <= 99; n++ {
 		for v := 0; v <= 99; v++ {
@@ -108,16 +132,6 @@ func slowPart2(prog []int) {
 	}
 }
 
-func part2(prog []int) {
-	target := 19690720
-	zeroVal := 610685
-	n := (target - zeroVal) / 360000
-	target = target % 1000
-	zeroVal = zeroVal % 1000
-	v := target - zeroVal
-	fmt.Println("Answer:", (100*n + v))
-}
-
 func printState(prog []int) {
 	fmt.Println(prog)
 }