b01 · September 20, 2024 15:51 · Sep 20, 2024
diff --git a/main.go b/main.go
@@ -0,0 +1,88 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func main() {
+
+}
+
+type proc struct {
+	id  string
+	sub string
+}
+
+func ProcessOrder(processes []*proc, p int) []string {
+	start := time.Now()
+	done := map[string]int{}
+	output := make([]string, 0, p)
+
+	fmt.Printf("waiting for all processes to complete\n")
+	fmt.Printf("start time: %v\n", start)
+
+	timeLeft := time.Until(time.Now().Add(time.Duration(time.Second * 1)))
+	fmt.Printf("time left %2v seconds\n", timeLeft)
+
+	elapsed := time.Now().Sub(start)
+	// Loop until time runs out.
+timeLoop:
+	for elapsed < timeLeft {
+		elapsed = time.Now().Sub(start)
+		fmt.Printf("time elapsed %v\n", elapsed)
+		// Loop until all processes are done
+		for i, process := range processes {
+			if process != nil && process.id == process.sub {
+				panic("parent process is equal to child process")
+			}
+
+			if process == nil {
+				continue
+			}
+
+			fmt.Printf("examine %v\n", process.id)
+			fmt.Printf("\t%v is waiting on %v\n", process.id, process.sub)
+			if find(processes, process.sub) == -1 {
+				fmt.Printf("\tsub process %v is done\n", process.sub)
+				_, ok := done[process.sub]
+				if !ok {
+					output = append(output, process.sub)
+				}
+				processes[i] = nil
+				done[process.sub] = 1
+			}
+
+			if find(processes, process.id) == -1 {
+				fmt.Printf("\tparent process %v is done\n", process.id)
+				_, ok := done[process.id]
+				if !ok {
+					output = append(output, process.id)
+				}
+				done[process.id] = 1
+			}
+
+			if len(output) >= p {
+				fmt.Printf("\tall processes are complete\n")
+				break timeLoop
+			}
+		}
+	}
+
+	fmt.Printf("output: %v\n", output)
+
+	return output
+}
+
+// find return index of item found or -1.
+func find(processes []*proc, id string) int {
+	rt := -1
+
+	for i, process := range processes {
+		if process != nil && process.id == id {
+			rt = i
+		}
+	}
+
+	return rt
+}
diff --git a/main_test.go b/main_test.go
@@ -0,0 +1,44 @@
+package main
+
+import (
+	"testing"
+)
+
+/* P1 -> P2,  P1 -> P4, P2 -> P3, P4 -> P5, 5 }
+
+Output: P2, P3, P5, P4, P1*/
+
+func TestProcessOrder(t *testing.T) {
+	cases := []struct {
+		name string
+		in   []*proc
+		pLen int
+		out  []string
+	}{
+		{
+			"1",
+			[]*proc{
+				{"P1", "P2"},
+				{"P1", "P4"},
+				{"P2", "P3"},
+				{"P4", "P5"},
+			},
+			5,
+			[]string{"P2", "P3", " P5", "P4", "P1"},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(d *testing.T) {
+			got := ProcessOrder(c.in, c.pLen)
+
+			for i, g := range got {
+				if g != c.out[i] {
+					d.Errorf("got %v, want %v\n", g, c.out[i])
+					break
+				}
+				i++
+			}
+		})
+	}
+}