排序小结(C语言)

排序

---

## Bubble_sort ##
void bublesort(int *a,int n)
{
    int i,j,t;
    for(i = 0;i<n-1;i++)
    {
      for(j = i+1;j<n;j++)
      {
          if(a[i]>a[j])
          {
              t = a[i];
              a[i] = a[j];
              a[j] = t;
          }
      }
    }
    return;
}
## Select_sort ##
void selectsort(int *a,int n)
{
    int i,j,k,t;
    for(i = 0;i<n - 1;i++)
    {
        k = i;
        for(j = i+1;j<n;j++)
        {
            if(a[k]>a[j])
                k = j;
        }
        if(k!=i)
        {
            t = a[k];
            a[k] = a[i];
            a[i] = t;
        }
    }
    return;
 }
 ## Quick_sort ##
 int findpos (int a[],int low,int high)
 {
    int val = a[low];
    while(low < high)
    {
        while(low< high && a[high] >=val)
            --high;
        a[low] = a[high];
        while(low<high && a[low] <= val)
           ++low;
        a[high] = a[low];
    }
        a[low] = val;
        return low;
}
void sort(int a[],int low,int high)
{
    int pos = findpos(a,low,high);
    if(low >= high)
        return;
    else
    {
        sort(a,low,pos - 1);
        sort(a,pos+1,high);
    }
    return;
}
## Insert_sort ##
void Insert_sort (int  a[],int n)
{
    int i,j,t;
    for(i = 1;i< n;i++){
       t = a[i];
    for(j = i - 1;j>=0 && a[j]>t;j--)
        a[j+1] = a[j];
     a[j+1] = t;
    }
     return;
}
## Shell_sort ##
void sort (int a[],int n)
{
    int k = n,i,j,t;
    while(k>0)
    {
        for(i = k;i<n;i++)
        {
            t = a[i];
            for(j = i - k;j>=0 && a[j] > t;j -= k)
                a[j+k] = a[j];
            a[j+k] = t;
        }
        k /= 2;
    }
    return;
}
## Merge_sort ##
void mergesort(int a[],int low,int high)
{
    int m = (low+high)/2;
    if(low == high)
        return;
    mergesort(a,low,m);
    mergesort(a,m+1,high);
    merge(a,low,m+1,high);
}
void merge(int a[],int low,int mid ,int high)
{
    int LEFT_SIZE = mid - low;
    int RIGHT_SIZE = high-mid+1;
    int left[LEFT_SIZE];
    int right[RIGHT_SIZE];
    int i = 0,j = 0,k =low;
    for(i = 0;i<mid;i++)
    left[i-low] = a[i];
    for(i =mid;i<=high;i++)
    right[i-mid] = a[i];
    i = 0;
    while(i<LEFT_SIZE && j<RIGHT_SIZE)
    {
        if(left[i] > right[j])
        {
            a[k] = right[j];
            j++;
            k++;
        }
        else
        {
            a[k] = left[i];
            i++;
            k++;
        }
    }
    while(i < LEFT_SIZE)
    {
           a[k] = left[i];
            i++;
            k++;
    }
    while(j < RIGHT_SIZE)
    {
        a[k] = right[j];
        j++;
        k++;
    }
    return;
}