Algoexpert - Algorithm

Author: VictorAlagwu

.idea/.gitignore

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+func main() {
+	arr := []int{1, 2, 3, 5, 6, 8, 9}
+	fmt.Println("Sorted Squared Array: O(nlogn) ", sortedSquaredArrayBruteForeApproach(arr))
+	fmt.Println("Sorted Squared Array: O(n)", sortedSquaredArraySolutionTwo(arr))
+}
+
+func sortedSquaredArrayBruteForeApproach(array []int) []int {
+	// Write your code here
+	arr := make([]int, len(array))
+
+	for idx, value := range array {
+		arr[idx] = value * value
+	}
+	sort.Ints(arr)
+	return arr
+}
+
+func sortedSquaredArraySolutionTwo(array []int) []int {
+	startIdx := 0
+	endIdx := len(array) - 1
+	currentIndex := 0
+	arr := make([]int, len(array))
+
+	for currentIndex < len(array) {
+		currentIndex += 1
+		arrayStartValue := array[startIdx] * array[startIdx]
+		arrayEndValue := array[endIdx] * array[endIdx]
+		if  arrayStartValue < arrayEndValue {
+			arr[len(array) - currentIndex] = arrayEndValue
+			endIdx -= 1
+		} else {
+			arr[len(array) - currentIndex] = arrayStartValue
+			startIdx += 1
+		}
+	}
+	return arr
+}

.idea/modules.xml

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"fmt"
+	//"sort"
+)
+
+func main() {
+	arr := []int{1,-2,3,4,-4,6,-14,8,2}
+
+	target := 4
+	fmt.Println("Number Sum: O(n^2)", twoNumberSumSolutionOne(arr, target))
+	fmt.Println("Number Sum: O(n)", twoNumberSumSolutionTwo(arr, target))
+}
+
+func twoNumberSumSolutionOne(array []int, target int) []int {
+	for i := 0; i < len(array); i++ {
+		for j := i + 1; j < len(array); j++ {
+			if array[i] == array[j] {
+				continue;
+			}
+			if array[i] + array[j] == target {
+				return []int{array[i],  array[j]}
+			}
+		}
+	}
+
+	return []int{}
+}
+
+func twoNumberSumSolutionTwo(array []int, target int) []int {
+	nums := map[int]bool{}
+
+	for _, num := range array {
+		checkValue := target - num
+		if _, found := nums[checkValue]; found {
+			return []int{checkValue, num}
+		}
+		nums[num] = true
+	}
+	return []int{}
+}

.idea/random-golang-ds-algorithms.iml

@@ -0,0 +1,28 @@
+package main
+
+import "fmt"
+
+func main() {
+	arr := []int{5, 1, 22, 25, 6, -1, 8, 10}
+	sequence := []int{1, 6, -1, 10}
+	fmt.Println("Number Sum: O(n)", isValidSubsequence(arr, sequence))
+}
+
+func isValidSubsequence(array []int, sequence []int) bool {
+	// Write your code here.
+	arrayIdx := 0
+	sequenceIdx := 0
+
+	for  arrayIdx < len(array) && sequenceIdx < len(sequence) {
+		if array[arrayIdx] == sequence[sequenceIdx] {
+			sequenceIdx ++
+		}
+		arrayIdx++
+	}
+	
+	if len(sequence) == sequenceIdx {
+		return true
+	} else {
+		return false
+	}
+}

.idea/vcs.xml

@@ -0,0 +1,3 @@
+module random-golang-algorithms
+
+go 1.17