problem12

Author: TipsyPixie

README.md

@@ -9,7 +9,7 @@ Solutions for [Daily Coding Problem](https://www.dailycodingproblem.com/ "Daily
 
 Run `make test` to test the solutions.
 ```bash
-make test NO=1 # test problem1
+make test NO=001 # test problem1
 make test # test all
 ```
 

problem011/problem011.go

@@ -42,22 +42,22 @@ func (node *trie) Find(query string) []string {
 	var result []string
 	if len(queryLeft) == 0 {
 		prefix := prefixBuilder.String()
-		for _, substring := range cursor.getStrings() {
+		for _, substring := range cursor.subStrings() {
 			result = append(result, fmt.Sprintf("%s%s", prefix, substring))
 		}
 	}
 	return result
 }
 
-func (node *trie) getStrings() []string {
+func (node *trie) subStrings() []string {
 	if len(*node) == 0 {
 		return []string{""}
 	}
 	childrenChannel := make(chan []string, len(*node))
 	for keyString, subNode := range *node {
 		go func(prefix string, node *trie) {
 			var subStrings []string
-			for _, subSubString := range node.getStrings() {
+			for _, subSubString := range node.subStrings() {
 				subStrings = append(subStrings, fmt.Sprintf("%s%s", prefix, subSubString))
 			}
 			childrenChannel <- subStrings

problem012/README.md

@@ -0,0 +1,19 @@
+## Daily Coding Problem: Problem #12 [Hard]
+
+Good morning! Here's your coding interview problem for today.
+
+This problem was asked by Amazon.
+
+There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time. Given N, write a function that returns the number of unique ways you can climb the staircase. The order of the steps matters.
+
+For example, if N is 4, then there are 5 unique ways:
+
+---
+* 1, 1, 1, 1
+* 2, 1, 1
+* 1, 2, 1
+* 1, 1, 2
+* 2, 2
+---
+
+What if, instead of being able to climb 1 or 2 steps at a time, you could climb any number from a set of positive integers X? For example, if X = {1, 3, 5}, you could climb 1, 3, or 5 steps at a time.

problem012/problem012.go

@@ -0,0 +1,14 @@
+package problem012
+
+func Run(maxStairCount int, stepSizes []int) int {
+	waysToClimb := make([]int, maxStairCount+1, maxStairCount+1)
+	waysToClimb[0] = 1
+	for stairCount := 1; stairCount <= maxStairCount; stairCount++ {
+		for _, stepSize := range stepSizes {
+			if stepSize <= stairCount {
+				waysToClimb[stairCount] += waysToClimb[stairCount-stepSize]
+			}
+		}
+	}
+	return waysToClimb[maxStairCount]
+}

problem012/problem012_test.go

@@ -0,0 +1,13 @@
+package problem012
+
+import "testing"
+
+func TestRun(t *testing.T) {
+	if Run(4, []int{1, 2}) != 5 {
+		t.FailNow()
+	}
+}
+
+func TestRun2(t *testing.T) {
+	t.Log(Run(20, []int{1, 3, 5}))
+}