基数排序LSD_Radix_Sort

Posted 2020-08-25 HITLJR

裸基数排序

#include <iostream>
using namespace std;
struct list_
{
    int v;
    int next;
}a[1005];
void print(list_ a[],int head)
{
    for (int i = head; i != -1; i = a[i].next)
    {
        cout << a[i].v <<" ";
    }
    cout << endl;
}
int LSD_radix_sort(list_ a[],int head,int digit)
{
    int first[10];
    int rear[10];
    int M = 1;
    for (int i = 1; i<=digit; i++)
    {
        for (int j = 0;j<=9;j++)
            first [j] = rear [j] = -1;
        int now = head;
        /***将数据分配到各个箱子中去***/
        while (head!=-1)
        {
            int radix = (a[head].v/M) % 10;
            if (first[radix] == -1)
              first [radix] = rear [radix] = head;
            else
            {
                a[rear[radix]].next = head;
                rear[radix] = head;
            }
            head = a[head].next;
        }
        /***连接各个箱子***/
        int ptr = -1;
        for (int j = 9;j >=0 ; j--)
            if (first[j] != -1)
            {
                a[rear[j]].next = ptr;
                ptr = first[j];
            }
        head = ptr;
        print(a,head);
        M*=10;
    }
    return head;
}
int main ()
{
    int n;
    int digit;
    cin >>n >> digit;
    for (int i =  1; i<=n; i++)
    {
        cin >> a[i].v;
        a[i].next = i+1;
    }
    a[n].next = -1;
    int head = LSD_radix_sort(a,1,digit);
    print(a,head);
}

LSD_Radix_Sort