###### tags: `LeetCode` `HackRank`
# HackRank Minimum Swaps 2

## Goal

尋找最小交換次數，將陣列排序好

## Solution

func minimumSwaps(arr []int32) int32 {

    intital := make([]int32, len(arr), (cap(arr)+1)*2)
    copy(intital,arr)
    quicksort(arr) //先排序找到最後目標
    var Map map[int32]int32
    Map = make(map[int32]int32)

    //建立目標索引
    for i ,value := range(arr) {
        Map[value] = int32(i)
    }
    count := int32(0)
    index := int32(0)
    
    //當前陣列與目標陣列不同時將目標陣列的時候,用索引找交換的位置
    //重覆到陣列完全相同
    for ;index < int32(len(arr)); {
        
        if ( arr[index] != intital[index]) {
            intital[index] , intital[ Map[intital[index]]] = intital[ Map[intital[index]]] , dest[index]
            count ++
        } else {
            index++
        }
        
    }
    index++
    return count
}

func quicksort(a []int32 ) {
    if len(a) < 2 {
        return 
    }
    
    left , right := 0 , len(a)-1
    
    pivot := rand.Int() % len(a)
    
    a[pivot] , a[right] = a[right] , a[pivot]
    
    for i,_ := range a {
        if a[i] < a[right] {
            a[left] , a[i] = a[i] , a[left]
            left++
        }
    }
    
    a[left],a[right] = a[right],a[left]
    
    quicksort(a[:left])
    quicksort(a[left+1:])
    
    return 
}