feat:slice LastIndexOf

Author: jin06

.gitignore

@@ -19,3 +19,4 @@ vendor/
 
 # Go workspace file
 go.work
+.vscode/

slice/index.go

@@ -19,3 +19,26 @@ func IndexOf[T comparable](array []T, value T, from int) int {
 	}
 	return -1
 }
+
+// LastIndexOf
+// This method is like IndexOf except that it iterates over elements of array from right to left.
+func LastIndexOf[T comparable](array []T, value T, from int) int {
+	var end int
+	if from >= 0 {
+		end = len(array) - 1 - from
+	} else {
+		end = -from - 1
+	}
+	if end < 0 {
+		return -1
+	}
+	if end >= len(array) {
+		end = len(array) - 1
+	}
+	for i := end; 0 <= end; i-- {
+		if array[i] == value {
+			return i
+		}
+	}
+	return -1
+}

slice/index_test.go

@@ -18,3 +18,14 @@ func ExampleIndexOf() {
 	//5
 	//1
 }
+
+func ExampleLastIndexOf() {
+	arr1 := []int{2, 3, 2, 3, 1}
+	fmt.Println(LastIndexOf(arr1, 3, 0))
+	fmt.Println(LastIndexOf(arr1, 3, 2))
+	fmt.Println(LastIndexOf(arr1, 3, -3))
+	//Output:
+	//3
+	//1
+	//1
+}