C++实现链式基数排序

Posted 2021-05-23 Wecccccccc

代码如下:

#include <iostream>
#include <cmath>
using namespace std;
typedef int KeyType;
const int END = -1;
const int Radix = 10;

typedef struct Node
{
	KeyType key;
	struct Node *next;
};

Node *CreateList()
{
	KeyType x;
	Node *q = nullptr;
	cin >> x;
	while (x != END)
	{
		Node *p = new Node;
		p->key = x;
		p->next = q;
		q = p;
		cin >> x;
	}
	return q;
}

int FindDigits(Node *p)
{
	int max = -1;
	while (p)
	{
		if (p->key > max) max = p->key;
		p = p->next;
	}

	int digits = 1;
	while (max / 10 > 0)
	{
		digits++;
		max = max / 10;
	}
	return digits;
}


void Distribute(Node *&p,int digits, Node *f[], Node *r[])
{
	Node *q;
	while (p)
	{
		q = p;
		p = p->next;
		int k = q->key;
		int radix = static_cast<int>(k / pow(10, digits - 1)) % 10;
		if (r[radix] == nullptr)
		{
			r[radix] = q;
			f[radix] = q;
			r[radix]->next = nullptr;
		}
		else
		{
			q->next = r[radix]->next;
			r[radix]->next = q;
			r[radix] = q;
		}
	}
}

void Collect(Node *&p, Node *f[], Node *r[])
{
	p = nullptr;
	for (int i = Radix - 1; i >= 0; i--)
	{
		if (f[i] != nullptr)
		{
			r[i]->next = p;
			p = f[i];
			r[i] = nullptr;//不要忘记这两步!!!
			f[i] = nullptr;
		}
	}
}

void RadixSort(Node *&p)
{
	Node *f[Radix], *r[Radix];
	for (int i = 0; i < Radix; i++)
	{
		f[i] = nullptr;
		r[i] = nullptr;
	}
	int digits = FindDigits(p);
	for (int i = 1; i <= digits; i++)
	{
		Distribute(p, i, f, r);
		Collect(p, f, r);
	}
}

void PrintElem(Node *p)
{
	while (p)
	{
		cout << p->key << " ";
		p = p->next;
	}
	cout << endl;
}

int main()
{
	Node *p;
	p = CreateList();
	PrintElem(p);
	cout << FindDigits(p) << endl;
	RadixSort(p);
	PrintElem(p);
	return 0;
}