Merge pull request #234 from vaskoz/day110

Day110

README.md

@@ -119,4 +119,5 @@ problems from
 * [Day 107](https://github.com/vaskoz/dailycodingproblem-go/issues/225)
 * [Day 108](https://github.com/vaskoz/dailycodingproblem-go/issues/227)
 * [Day 109](https://github.com/vaskoz/dailycodingproblem-go/issues/229)
+* [Day 110](https://github.com/vaskoz/dailycodingproblem-go/issues/231)
 * [Day 111](https://github.com/vaskoz/dailycodingproblem-go/issues/232)

day110/problem.go

@@ -0,0 +1,32 @@
+package day110
+
+// IntBinaryTree is a binary tree with values that are integers.
+type IntBinaryTree struct {
+	Value       int
+	Left, Right *IntBinaryTree
+}
+
+// AllPathsToLeaves return the nodes encountered from the root
+// to each leave.
+func AllPathsToLeaves(tree *IntBinaryTree) [][]int {
+	return pathHolder(tree, []int{})
+}
+
+func pathHolder(tree *IntBinaryTree, path []int) [][]int {
+	path = append(path, tree.Value)
+	if tree.Left == nil && tree.Right == nil {
+		leavePath := make([]int, len(path))
+		copy(leavePath, path)
+		return [][]int{leavePath}
+	}
+	var result [][]int
+	if tree.Left != nil {
+		leftSubtree := pathHolder(tree.Left, path)
+		result = append(result, leftSubtree...)
+	}
+	if tree.Right != nil {
+		rightSubtree := pathHolder(tree.Right, path)
+		result = append(result, rightSubtree...)
+	}
+	return result
+}

day110/problem_test.go

@@ -0,0 +1,35 @@
+package day110
+
+import (
+	"reflect"
+	"testing"
+)
+
+var testcases = []struct {
+	head     *IntBinaryTree
+	expected [][]int
+}{
+	{&IntBinaryTree{Value: 1,
+		Left: &IntBinaryTree{2, nil, nil},
+		Right: &IntBinaryTree{3,
+			&IntBinaryTree{4, nil, nil},
+			&IntBinaryTree{5, nil, nil}}},
+		[][]int{{1, 2}, {1, 3, 4}, {1, 3, 5}}},
+}
+
+func TestAllPathsToLeaves(t *testing.T) {
+	t.Parallel()
+	for _, tc := range testcases {
+		if result := AllPathsToLeaves(tc.head); !reflect.DeepEqual(tc.expected, result) {
+			t.Errorf("Expected %v got %v", tc.expected, result)
+		}
+	}
+}
+
+func BenchmarkAllPathsToLeaves(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			AllPathsToLeaves(tc.head)
+		}
+	}
+}