How to sort using quick sort in C language

Arrangement method of quick sorting method: First, set a reference point every time you sort, put all the numbers less than or equal to the reference point to the left of the reference point; then put all the numbers greater than or equal to the reference point To the right of the reference point; finally, every exchange will not be like bubble sorting where only adjacent numbers can be exchanged each time, and the exchange distance will be much larger.

Quick sorting method:

Algorithm idea:

(1) We select a record (usually the first one) from the record sequence to be sorted as the reference element (called key) key=arr[left], and then set two variables, left points to the leftmost part of the sequence , right points to the rightmost part of the data.

(2) key is first compared with arr[right]. If arr[right]key, then we only need to compare right--, right--, and then compare arr[right] with key until arr[right]

(3) If there is arr[right]key, then arr[right]=arr[left]. If arr[left]

(4) Then move right and repeat the above steps

(5) Finally get {23 58 13 10 57 62} 65 {106 78 95 85}, and then perform the same operation on the left subarray and right subarray. Finally, an ordered sequence is obtained.

Algorithm implementation:

public class QuickSort {
 
   public static void quickSort(int [] arr,int left,int right) {
      int pivot=0;
      if(left<right) {
         pivot=partition(arr,left,right);
         quickSort(arr,left,pivot-1);
         quickSort(arr,pivot+1,right);
      }
   }
 
   private static int partition(int[] arr,int left,int right) {
      int key=arr[left];
      while(left<right) {
         while(left<right && arr[right]>=key) {
            right--;
         }
         arr[left]=arr[right];
         while(left<right && arr[left]<=key) {
            left++;
         }
         arr[right]=arr[left];
      }
      arr[left]=key;
      return left;
   }
  
   public static void main(String[] args) {
      int arr[]= {65,58,95,10,57,62,13,106,78,23,85};
      System.out.println("排序前："+Arrays.toString(arr));
      quickSort(arr,0,arr.length-1);
      System.out.println("排序后："+Arrays.toString(arr));
   }
}

排序前：[65, 58, 95, 10, 57, 62, 13, 106, 78, 23, 85]
排序后：[10, 13, 23, 57, 58, 62, 65, 78, 85, 95, 106]

Related learning recommendations: C video tutorial

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