Add solution for Challenge 19 by yz4230

challenge-19/submissions/yz4230/solution-template.go

@@ -0,0 +1,79 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+func main() {
+	// Example slice for testing
+	numbers := []int{3, 1, 4, 1, 5, 9, 2, 6}
+
+	// Test FindMax
+	max := FindMax(numbers)
+	fmt.Printf("Maximum value: %d\n", max)
+
+	// Test RemoveDuplicates
+	unique := RemoveDuplicates(numbers)
+	fmt.Printf("After removing duplicates: %v\n", unique)
+
+	// Test ReverseSlice
+	reversed := ReverseSlice(numbers)
+	fmt.Printf("Reversed: %v\n", reversed)
+
+	// Test FilterEven
+	evenOnly := FilterEven(numbers)
+	fmt.Printf("Even numbers only: %v\n", evenOnly)
+}
+
+// FindMax returns the maximum value in a slice of integers.
+// If the slice is empty, it returns 0.
+func FindMax(numbers []int) int {
+    if len(numbers) == 0 {
+        return 0
+    }
+
+	ret := math.MinInt
+	for _, n := range numbers {
+	    if ret < n {
+	        ret = n
+	    }
+	}
+
+	return ret
+}
+
+// RemoveDuplicates returns a new slice with duplicate values removed,
+// preserving the original order of elements.
+func RemoveDuplicates(numbers []int) []int {
+    ret := make([]int, 0, len(numbers))
+	appeared := map[int]struct{}{}
+	for _, n := range numbers {
+	    if _, ok := appeared[n]; !ok {
+	        ret = append(ret, n)
+	        appeared[n] = struct{}{}
+	    }
+	}
+	return ret
+}
+
+// ReverseSlice returns a new slice with elements in reverse order.
+func ReverseSlice(slice []int) []int {
+	ret := make([]int, 0, len(slice))
+	for i := range slice {
+	    ret = append(ret, slice[len(slice)-i-1])
+	}
+	return ret
+}
+
+// FilterEven returns a new slice containing only the even numbers
+// from the original slice.
+func FilterEven(numbers []int) []int {
+    ret := make([]int, 0, len(numbers))
+	for _, n := range numbers {
+	    if n % 2 == 0 {
+	        ret = append(ret, n)
+	    }
+	}
+	return ret
+}