day20: wrong solution for part two

Author: fxnn

day20/main.go

@@ -5,6 +5,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"sync"
 
 	"github.com/fxnn/adventofcode2024/util"
 )
@@ -151,12 +152,29 @@ func main() {
 	var moves = findMoves(course)
 	var time = len(moves) - 1
 	fmt.Printf("course takes %d picoseconds\n", time)
-	var cheats = make(map[cheat]util.Void)
+
+	var cheatChan = make(chan cheat)
+	var inProgressMoves sync.WaitGroup
 	for i := range moves {
-		for _, c := range findCheats(course, moves, i, *minSaving, *debug) {
-			cheats[c] = util.Void{}
-		}
-		fmt.Printf("searched cheats for %d/%d moves\n", i+1, len(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{}
+	}
+
 	fmt.Printf("found %d unique cheats saving >= %d picoseconds", len(cheats), *minSaving)
 }