完善Remove
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huangsimin
@@ -1,108 +1,218 @@
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package arraylist
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import (
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"fmt"
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"strings"
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"github.com/emirpasic/gods/lists"
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"github.com/emirpasic/gods/utils"
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)
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func assertListImplementation() {
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var _ lists.List = (*ArrayList)(nil)
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}
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type ArrayList struct {
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data []interface{}
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headIndex uint
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nextIndex uint
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size uint
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reserveHead uint
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reserveLimit uint
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growSize uint
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shrinkSize uint
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size int
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}
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func New() *ArrayList {
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al := &ArrayList{}
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al.reserveHead = 2
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al.reserveLimit = 256
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al.headIndex = al.reserveHead
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al.nextIndex = al.headIndex
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const (
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growthFactor = float32(2.0) // growth by 100%
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shrinkFactor = float32(0.25) // shrink when size is 25% of capacity (0 means never shrink)
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)
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al.data = make([]interface{}, 8, 8)
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return al
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}
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func (l *ArrayList) Size() uint {
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return l.size
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}
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func (l *ArrayList) grow() {
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newsize := uint(len(l.data)) << 1
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if l.reserveHead < l.reserveLimit {
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l.reserveHead = l.reserveHead << 1
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// New instantiates a new list and adds the passed values, if any, to the list
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func New(values ...interface{}) *ArrayList {
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list := &ArrayList{}
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if len(values) > 0 {
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list.Add(values...)
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}
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l.headIndex = l.reserveHead
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l.nextIndex = l.headIndex
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l.data = make([]interface{}, newsize, newsize)
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return list
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}
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// Add add value to the tail of list
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func (l *ArrayList) Add(v interface{}) {
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if l.nextIndex >= uint(len(l.data)) {
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l.grow()
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// Add appends a value at the end of the list
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func (list *ArrayList) Add(values ...interface{}) {
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list.growBy(len(values))
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for _, value := range values {
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list.data[list.size] = value
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list.size++
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}
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l.size++
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l.data[l.nextIndex] = v
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// grow
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}
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// Push push is equal to add
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func (l *ArrayList) Push(v interface{}) {
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l.data = append(l.data, v)
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}
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// Get returns the element at index.
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// Second return parameter is true if index is within bounds of the array and array is not empty, otherwise false.
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func (list *ArrayList) Get(index int) (interface{}, bool) {
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func (l *ArrayList) Set(idx uint, value interface{}) {
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l.data[idx] = value
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}
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func (l *ArrayList) Get(idx uint) (result interface{}, isfound bool) {
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if idx >= l.Size() {
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return nil, false
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}
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return l.data[idx], true
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}
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func (l *ArrayList) Pop() (result interface{}, found bool) {
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if l.Size() == 0 {
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return nil, false
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}
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rindex := len(l.data) - 1
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result = l.data[rindex]
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l.data = l.data[0:rindex]
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return result, true
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}
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func (l *ArrayList) Remove(idx uint) (rvalue interface{}, isfound bool) {
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if idx >= l.Size() {
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if !list.withinRange(index) {
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return nil, false
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}
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rvalue = l.data[idx]
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l.data = append(l.data[0:idx], l.data[idx+1:])
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return rvalue, true
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return list.data[index], true
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}
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func (l *ArrayList) Values() (result []interface{}) {
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values := make([]interface{}, l.Size(), l.Size())
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copy(values, l.data)
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return values
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// Remove removes the element at the given index from the list.
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func (list *ArrayList) Remove(index int) {
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if !list.withinRange(index) {
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return
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}
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list.data[index] = nil // cleanup reference
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copy(list.data[index:], list.data[index+1:list.size]) // shift to the left by one (slow operation, need ways to optimize this)
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list.size--
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list.shrink()
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}
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func (l *ArrayList) Traversal(every func(index int, cur interface{}) bool) {
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for i, cur := range l.data {
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if !every(i, cur) {
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return
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// Contains checks if elements (one or more) are present in the set.
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// All elements have to be present in the set for the method to return true.
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// Performance time complexity of n^2.
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// Returns true if no arguments are passed at all, i.e. set is always super-set of empty set.
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func (list *ArrayList) Contains(values ...interface{}) bool {
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for _, searchValue := range values {
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found := false
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for _, element := range list.data {
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if element == searchValue {
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found = true
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break
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}
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}
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if !found {
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return false
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}
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}
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return true
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}
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// Values returns all elements in the list.
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func (list *ArrayList) Values() []interface{} {
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newElements := make([]interface{}, list.size, list.size)
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copy(newElements, list.data[:list.size])
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return newElements
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}
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//IndexOf returns index of provided element
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func (list *ArrayList) IndexOf(value interface{}) int {
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if list.size == 0 {
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return -1
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}
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for index, element := range list.data {
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if element == value {
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return index
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}
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}
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return -1
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}
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// Empty returns true if list does not contain any elements.
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func (list *ArrayList) Empty() bool {
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return list.size == 0
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}
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// Size returns number of elements within the list.
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func (list *ArrayList) Size() int {
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return list.size
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}
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// Clear removes all elements from the list.
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func (list *ArrayList) Clear() {
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list.size = 0
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list.data = []interface{}{}
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}
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// Sort sorts values (in-place) using.
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func (list *ArrayList) Sort(comparator utils.Comparator) {
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if len(list.data) < 2 {
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return
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}
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utils.Sort(list.data[:list.size], comparator)
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}
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// Swap swaps the two values at the specified positions.
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func (list *ArrayList) Swap(i, j int) {
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if list.withinRange(i) && list.withinRange(j) {
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list.data[i], list.data[j] = list.data[j], list.data[i]
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}
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}
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// Insert inserts values at specified index position shifting the value at that position (if any) and any subsequent elements to the right.
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// Does not do anything if position is negative or bigger than list's size
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// Note: position equal to list's size is valid, i.e. append.
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func (list *ArrayList) Insert(index int, values ...interface{}) {
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if !list.withinRange(index) {
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// Append
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if index == list.size {
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list.Add(values...)
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}
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return
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}
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l := len(values)
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list.growBy(l)
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list.size += l
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copy(list.data[index+l:], list.data[index:list.size-l])
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copy(list.data[index:], values)
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}
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// Set the value at specified index
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// Does not do anything if position is negative or bigger than list's size
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// Note: position equal to list's size is valid, i.e. append.
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func (list *ArrayList) Set(index int, value interface{}) {
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if !list.withinRange(index) {
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// Append
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if index == list.size {
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list.Add(value)
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}
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return
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}
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list.data[index] = value
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}
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// String returns a string representation of container
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func (list *ArrayList) String() string {
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str := "ArrayList\n"
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values := []string{}
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for _, value := range list.data[:list.size] {
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values = append(values, fmt.Sprintf("%v", value))
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}
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str += strings.Join(values, ", ")
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return str
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}
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// Check that the index is within bounds of the list
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func (list *ArrayList) withinRange(index int) bool {
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return index >= 0 && index < list.size
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}
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func (list *ArrayList) resize(cap int) {
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newElements := make([]interface{}, cap, cap)
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copy(newElements, list.data)
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list.data = newElements
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}
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// Expand the array if necessary, i.e. capacity will be reached if we add n elements
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func (list *ArrayList) growBy(n int) {
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// When capacity is reached, grow by a factor of growthFactor and add number of elements
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currentCapacity := cap(list.data)
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if list.size+n >= currentCapacity {
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newCapacity := int(growthFactor * float32(currentCapacity+n))
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list.resize(newCapacity)
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}
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}
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// Shrink the array if necessary, i.e. when size is shrinkFactor percent of current capacity
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func (list *ArrayList) shrink() {
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if shrinkFactor == 0.0 {
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return
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}
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// Shrink when size is at shrinkFactor * capacity
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currentCapacity := cap(list.data)
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if list.size <= int(float32(currentCapacity)*shrinkFactor) {
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list.resize(list.size)
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}
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}
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