From c87e4038aaf59b84d1e4a05a37593befb1944abd Mon Sep 17 00:00:00 2001
From: Felix Neumann <dev@fxnn.de>
Date: Mon, 23 Dec 2024 00:06:10 +0100
Subject: [PATCH] day20: removed unnecessary parallelization

---
 day20/main.go | 28 +++++++---------------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/day20/main.go b/day20/main.go
index 7473031..dcb7b8b 100644
--- a/day20/main.go
+++ b/day20/main.go
@@ -5,7 +5,6 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"sync"
 
 	"github.com/fxnn/adventofcode2024/util"
 )
@@ -156,27 +155,14 @@ func main() {
 	var time = len(moves) - 1
 	fmt.Printf("course takes %d picoseconds\n", time)
 
-	var cheatChan = make(chan cheat)
-	var inProgressMoves sync.WaitGroup
-	for i := range moves {
-		inProgressMoves.Add(1)
-		go func(startIdx int) {
-			defer inProgressMoves.Done()
-			for _, c := range findCheats(course, moves, startIdx, *minSaving, *debug) {
-				cheatChan <- c
-			}
-			fmt.Printf("searched cheats for %d/%d moves\n", startIdx+1, len(moves))
-		}(i)
-	}
-
-	go func() {
-		inProgressMoves.Wait()
-		close(cheatChan)
-	}()
-
 	var cheats = make(map[cheat]util.Void)
-	for c := range cheatChan {
-		cheats[c] = util.Void{}
+	for startIdx := range moves {
+		for _, c := range findCheats(course, moves, startIdx, *minSaving, *debug) {
+			cheats[c] = util.Void{}
+		}
+		if startIdx%100 == 0 {
+			fmt.Printf("searched cheats for %d/%d moves\n", startIdx+1, len(moves))
+		}
 	}
 
 	fmt.Printf("found %d unique cheats saving >= %d picoseconds", len(cheats), *minSaving)