sorting - quick sort

Posted 2022-12-07 小马识图

#include "stdio.h"
#include "string.h"

#define MAX_LIST 50

typedef struct _SqList 
    int data[MAX_LIST];
    int length;
SqList;

//The flesh of QSort lies in Partition, it chooses one element(pivot) from the array 
//moves elements around to render the array in a state that everything before the pivot
//is smaller than pivot whilst everything after pivot is larger. The sort can continue 
//on these two sub-arraies. The rationale behind this sorting algorithm is to bisect the 
//array and recursively sorting on sub-array. 
int Partition( SqList* L, int start, int end )

    int temp = L->data[start];

    while( start < end )
    
        while(start < end &&  L->data[end] >= temp )
            end--;
        L->data[start] = L->data[end];
        while( start < end && L->data[start] <= temp )
            start++;
        L->data[end] = L->data[start];
    
    L->data[start] = temp;
    return start;

void QSort( SqList* L, int start, int end )

    if( start < end )
    
        int pivot = Partition(L, start, L->length-1 );
        QSort( L, start, pivot - 1 );
        QSort( L, pivot + 1, end );
    

void QuickSort(SqList* L)

    QSort(L, 0, L->length-1);   


int main()

    SqList d;
    int intarr[] = 1,10,23,48,65,31,-21,9,88,100;
    memcpy( d.data, intarr, sizeof(intarr));
    d.length = sizeof(intarr)/sizeof(int);  
    int index = 0;
    printf("Original array:\\n");
    for( ; index < d.length; index++ )
        printf(" %d", d.data[index] );
    printf("\\nQuick sort...\\n");
    QuickSort( &d );
    for( index = 0; index < d.length; index++ )
        printf(" %d", d.data[index] );
    printf("\\n");
    return 0;