Merge pull request #27 from StevanFreeborn/stevanfreeborn/feat/day-eleven-part-dos

feat: day eleven part two solved

.gitignore

@@ -1,4 +1,4 @@
-**/*/EXAMPLE.txt
+**/*/EXAMPLE*.txt
 **/*/INPUT.txt
 **/*/PROBLEM.md
 

cmd/11/main.go

@@ -4,11 +4,15 @@ import (
 	"strings"
 
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/file"
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/queue"
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/stack"
 )
 
-const START_NODE = "you"
-const END_NODE = "out"
+const YOU_NODE = "you"
+const OUT_NODE = "out"
+const SVR_NODE = "svr"
+const DAC_NODE = "dac"
+const FFT_NODE = "fft"
 
 func SolvePartOne(filePath string) int {
 	adjacencyList := map[string][]string{}
@@ -21,13 +25,13 @@ func SolvePartOne(filePath string) int {
 	}
 
 	stack := stack.New[string]()
-	stack.Push(START_NODE)
+	stack.Push(YOU_NODE)
 	pathCount := 0
 
 	for stack.IsEmpty() == false {
 		current, _ := stack.Pop()
 
-		if current == END_NODE {
+		if current == OUT_NODE {
 			pathCount++
 			continue
 		}
@@ -41,3 +45,73 @@ func SolvePartOne(filePath string) int {
 
 	return pathCount
 }
+
+func SolvePartTwo(filePath string) int {
+	adjacencyList := map[string][]string{}
+	inDegrees := map[string]int{}
+	allNodes := map[string]bool{}
+
+	for line := range file.ReadLines(filePath) {
+		parts := strings.Split(line, ": ")
+		from := parts[0]
+		toList := strings.Split(parts[1], " ")
+
+		allNodes[from] = true
+
+		_, existingInDegrees := inDegrees[from]
+
+		if existingInDegrees == false {
+			inDegrees[from] = 0
+		}
+
+		for _, to := range toList {
+			allNodes[to] = true
+			adjacencyList[from] = append(adjacencyList[from], to)
+			inDegrees[to]++
+		}
+	}
+
+	queue := queue.New[string]()
+
+	for node := range allNodes {
+		if inDegrees[node] == 0 {
+			queue.Enqueue(node)
+		}
+	}
+
+	processOrder := []string{}
+
+	for queue.IsEmpty() == false {
+		current, _ := queue.Dequeue()
+		processOrder = append(processOrder, current)
+
+		for _, neighbor := range adjacencyList[current] {
+			inDegrees[neighbor]--
+
+			if inDegrees[neighbor] == 0 {
+				queue.Enqueue(neighbor)
+			}
+		}
+	}
+
+	pathA := countPaths(SVR_NODE, FFT_NODE, processOrder, adjacencyList) * countPaths(FFT_NODE, DAC_NODE, processOrder, adjacencyList) * countPaths(DAC_NODE, OUT_NODE, processOrder, adjacencyList)
+	pathB := countPaths(SVR_NODE, DAC_NODE, processOrder, adjacencyList) * countPaths(DAC_NODE, FFT_NODE, processOrder, adjacencyList) * countPaths(FFT_NODE, OUT_NODE, processOrder, adjacencyList)
+	return pathA + pathB
+}
+
+func countPaths(start string, end string, processOrder []string, adjacencyList map[string][]string) int {
+	pathsCount := map[string]int{}
+	pathsCount[start] = 1
+
+	for _, item := range processOrder {
+		if pathsCount[item] == 0 {
+			continue
+		}
+
+		for _, n := range adjacencyList[item] {
+			pathsCount[n] += pathsCount[item]
+		}
+	}
+
+	return pathsCount[end]
+}

cmd/11/main_test.go

@@ -9,10 +9,10 @@ import (
 func TestSolvePartOneWithExampleInput(t *testing.T) {
 	expected := 5
 
-	result := solution.SolvePartOne("EXAMPLE.txt")
+	result := solution.SolvePartOne("EXAMPLE_ONE.txt")
 
 	if result != expected {
-		t.Errorf("SolvePartOne(EXAMPLE.txt) = %d; want %d", result, expected)
+		t.Errorf("SolvePartOne(EXAMPLE_ONE.txt) = %d; want %d", result, expected)
 	}
 }
 
@@ -25,3 +25,23 @@ func TestSolvePartOneWithInput(t *testing.T) {
 		t.Errorf("SolvePartOne(INPUT.txt) = %d; want %d", result, expected)
 	}
 }
+
+func TestSolvePartTwoWithExampleInput(t *testing.T) {
+	expected := 2
+
+	result := solution.SolvePartTwo("EXAMPLE_TWO.txt")
+
+	if result != expected {
+		t.Errorf("SolvePartTwo(EXAMPLE_TWO.txt) = %d; want %d", result, expected)
+	}
+}
+
+func TestSolvePartTwoWithInput(t *testing.T) {
+	expected := 393_474_305_030_400
+
+	result := solution.SolvePartTwo("INPUT.txt")
+
+	if result != expected {
+		t.Errorf("SolvePartTwo(INPUT.txt) = %d; want %d", result, expected)
+	}
+}