Quick Sort and Merge sort (C language)

1.0 Quick Sort algorithm

(1) Decomposition (2) recursive solution (3) merging

int partition (int a[],int p,int R)

{

int i=p,j=r+1;

int x=a[p];

int temp;

while (1)//swap elements of <x to the left element, >x elements swap to the right element

{

while (a[++i]<x && i<r);

while (A[--J]>X);

if (I>=J)

Break

Temp=a[i];

A[I]=A[J];

A[j]=temp;

}

A[P]=A[J];

A[j]=x;

Return J;

}

void QSort (int a[],int p,int r,int num)

{

int i;

if (p<r)

{

int q=partition (A,P,R);

QSort (A,p,q-1,num); Sort the left half of the paragraph

QSort (A,q+1,r,num); Sort the right half of the paragraph

}

printf (" Quick sort process:");

for (i=0;i<num;i++)

{

printf ("%d", a[i]);

}

printf ("\ n");

}

int main ()

{

int num;

int i;

int a[100];

printf (" Please enter array length:");

scanf ("%d", &num);

printf (" please input array:\ n");

for (i=0;i<num;i++)

{

scanf ("%d", &a[i]);

}

QSort (A,0,num-1,num);

printf (" quick sort Result:");

for (i=0;i<num;i++)

{

printf ("%d", a[i]);

}

return 0;

}

2.0 Merge Sort algorithm

Combine two ordered left and right sub-tables (in mid) into an ordered table

void merge (int a[],int first,int mid,int last)

{

int Indexa=first;

int indexb=mid+1;

int tempindex=0;

int i;

static int temp[1000];

while (Indexa<=mid && indexb<=last)//to traverse the left and right sub-tables, if one of the sub-tables is traversed, jump out of the loop

{

if (A[indexa]<a[indexb])

{

Temp[tempindex++]=a[indexa++];

}

Else

{

Temp[tempindex++]=a[indexb++];

}

}

　　　　Once a child table has been traversed, jump out of the loop and put the remainder of the other side of the child table into the staging array (ordered)

while (Indexa<=mid)

{

Temp[tempindex++]=a[indexa++];

}

while (Indexb<=last)

{

Temp[tempindex++]=a[indexb++];

}

Writes an ordered sequence of columns in the staging array to the set position of the target array, making the sorted array segments orderly

tempindex=0;

for (i=first;i<=last;i++)

{

A[i]=temp[tempindex++];

}

}

void mergesort (int a[],int first,int last,int num)

{

int i;

if (first<last)//The length of the child table is greater than 1, then go to the following recursive processing

{

int mid= (first+last)/2;

MergeSort (A,first,mid,num);

MergeSort (A,mid+1,first,num);

Merge (A,first,mid,last);

}

printf (" array at merge sort:\ n");

for (i=0;i<num;i++)

{

printf ("%d", a[i]);

}

printf ("\ n");

}

int main ()

{

int num;

int i;

int a[100];

printf (" Please enter array length:");

scanf ("%d", &num);

printf (" please input array:\ n");

for (i=0;i<num;i++)

{

scanf ("%d", &a[i]);

}

MergeSort (A,0,num-1,num);

printf (" merge sorted array:\ n");

for (i=0;i<num;i++)

{

printf ("%d", a[i]);

}

return 0;

}

Quick Sort and Merge sort (C language)