package main
import "fmt"
// 冒泡排序
func BubbleSort(arr []int) {
    n := len(arr)
    for i := 0; i < n-1; i++ {
        for j := 0; j < n-i-1; j++ {
            if arr[j] > arr[j+1] {
                arr[j], arr[j+1] = arr[j+1], arr[j]
            }
        }
    }
}
// 選擇排序
func SelectionSort(arr []int) {
    n := len(arr)
    for i := 0; i < n-1; i++ {
        minIndex := i
        for j := i + 1; j < n; j++ {
            if arr[j] < arr[minIndex] {
                minIndex = j
            }
        }
        arr[i], arr[minIndex] = arr[minIndex], arr[i]
    }
}
// 插入排序
func InsertionSort(arr []int) {
    n := len(arr)
    for i := 1; i < n; i++ {
        key := arr[i]
        j := i - 1
        for j >= 0 && arr[j] > key {
            arr[j+1] = arr[j]
            j--
        }
        arr[j+1] = key
    }
}
// 希爾排序
func ShellSort(arr []int) {
    n := len(arr)
    gap := n / 2
    for gap > 0 {
        for i := gap; i < n; i++ {
            j := i
            for j-gap >= 0 && arr[j-gap] > arr[j] {
                arr[j-gap], arr[j] = arr[j], arr[j-gap]
                j -= gap
            }
        }
        gap /= 2
    }
}
// 歸并排序
func MergeSort(arr []int) []int {
    if len(arr) <= 1 {
        return arr
    }
    mid := len(arr) / 2
    left := MergeSort(arr[:mid])
    right := MergeSort(arr[mid:])
    return merge(left, right)
}
func merge(left, right []int) []int {
    result := make([]int, 0)
    i, j := 0, 0
    for i < len(left) && j < len(right) {
        if left[i] < right[j] {
            result = append(result, left[i])
            i++
        } else {
            result = append(result, right[j])
            j++
        }
    }
    result = append(result, left[i:]...)
    result = append(result, right[j:]...)
    return result
}
// 快速排序
func QuickSort(arr []int) {
    quickSort(arr, 0, len(arr)-1)
}
func quickSort(arr []int, left, right int) {
    if left < right {
        pivot := partition(arr, left, right)
        quickSort(arr, left, pivot-1)
        quickSort(arr, pivot+1, right)
    }
}
func partition(arr []int, left, right int) int {
    pivot := arr[right]
    i := left - 1
    for j := left; j < right; j++ {
        if arr[j] < pivot {
            i++
            arr[i], arr[j] = arr[j], arr[i]
        }
    }
    arr[i+1], arr[right] = arr[right], arr[i+1]
    return i + 1
}
// 堆排序
func HeapSort(arr []int) {
    n := len(arr)
    for i := n/2 - 1; i >= 0; i-- {
        heapify(arr, n, i)
    }
    for i := n - 1; i >= 0; i-- {
        arr[0], arr[i] = arr[i], arr[0]
        heapify(arr, i, 0)
    }
}
func heapify(arr []int, n, i int) {
    largest := i
    left := 2*i + 1
    right := 2*i + 2
    if left < n && arr[left] > arr[largest] {
        largest = left
    }
    if right < n && arr[right] > arr[largest] {
        largest = right
    }
    if largest != i {
        arr[i], arr[largest] = arr[largest], arr[i]
        heapify(arr, n, largest)
    }
}
// 計數排序
func CountingSort(arr []int) {
    n := len(arr)
    if n <= 1 {
        return
    }
    maxVal := arr[0]
    for i := 1; i < n; i++ {
        if arr[i] > maxVal {
            maxVal = arr[i]
        }
    }
    count := make([]int, maxVal+1)
    for i := 0; i < n; i++ {
        count[arr[i]]++
    }
    for i, j := 0, 0; i <= maxVal; i++ {
        for count[i] > 0 {
            arr[j] = i
            j++
            count[i]--
        }
    }
}
// 桶排序
func BucketSort(arr []int) {
    n := len(arr)
    if n <= 1 {
        return
    }
    maxVal := arr[0]
    minVal := arr[0]
    for i := 1; i < n; i++ {
        if arr[i] > maxVal {
            maxVal = arr[i]
        }
        if arr[i] < minVal {
            minVal = arr[i]
        }
    }
    bucketSize := 10
    bucketCount := (maxVal-minVal)/bucketSize + 1
    buckets := make([][]int, bucketCount)
    for i := 0; i < bucketCount; i++ {
        buckets[i] = make([]int, 0)
    }
    for i := 0; i < n; i++ {
        index := (arr[i] - minVal) / bucketSize
        buckets[index] = append(buckets[index], arr[i])
    }
    k := 0
    for i := 0; i < bucketCount; i++ {
        if len(buckets[i]) > 0 {
            InsertionSort(buckets[i])
            copy(arr[k:], buckets[i])
            k += len(buckets[i])
        }
    }
}
// 基數排序
func RadixSort(arr []int) {
    n := len(arr)
    if n <= 1 {
        return
    }
    maxVal := arr[0]
    for i := 1; i < n; i++ {
        if arr[i] > maxVal {
            maxVal = arr[i]
        }
    }
    exp := 1
    for maxVal/exp > 0 {
        countingSortForRadix(arr, exp)
        exp *= 10
    }
}
func countingSortForRadix(arr []int, exp int) {
    n := len(arr)
    count := make([]int, 10)
    output := make([]int, n)
    for i := 0; i < n; i++ {
        index := (arr[i] / exp) % 10
        count[index]++
    }
    for i := 1; i < 10; i++ {
        count[i] += count[i-1]
    }
    for i := n - 1; i >= 0; i-- {
        index := (arr[i] / exp) % 10
        output[count[index]-1] = arr[i]
        count[index]--
    }
    for i := 0; i < n; i++ {
        arr[i] = output[i]
    }
}
func main() {
    arr1 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr2 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr3 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr4 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr5 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr6 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr7 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr8 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr9 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    arr10 := []int{1, 3, 2, 5, 4, 7, 6, 9, 8}
    BubbleSort(arr1)
    fmt.Printf("arr1: %v\n", arr1)
    SelectionSort(arr2)
    fmt.Printf("arr2: %v\n", arr2)
    InsertionSort(arr3)
    fmt.Printf("arr3: %v\n", arr3)
    ShellSort(arr4)
    fmt.Printf("arr4: %v\n", arr4)
    arr5 = MergeSort(arr5)
    fmt.Printf("arr5: %v\n", arr5)
    QuickSort(arr6)
    fmt.Printf("arr6: %v\n", arr6)
    HeapSort(arr7)
    fmt.Printf("arr7: %v\n", arr7)
    CountingSort(arr8)
    fmt.Printf("arr8: %v\n", arr8)
    BucketSort(arr9)
    fmt.Printf("arr9: %v\n", arr9)
    RadixSort(arr10)
    fmt.Printf("arr10: %v\n", arr10)
}