uva-110-没有for循环的排序

题意:看输出就懂了,暴力枚举题,字符串最大长度是8,所有长度等于8的长度是8!=1x2x3x4x5x6x7x8=40320,数据量比较小的.只是枚举的方向比较怪异,如下,长度等于3的串

a

ab,ba

abc,acb,cab

bac,bca,cba

但是输出确实不好输出,事实上输出的位置是可用计算出来的.

解法:

组成一颗多叉树,根节点是a,那么第1层有俩个孩子,第二层有三个孩子,第三层有4个孩子,一直往下生成,到第八层,然后就是遍历这颗多叉树.

AC时间,80ms

2G内存的电脑还是能刷题的

#include <iostream>
#include <stdio.h>
#include<memory.h>
using namespace std;

const int N = 8;
#define null NULL
struct Node
{
	char a[8];
	int al;
	Node* cp[8];
	int cl;
	Node()
	{
		memset(a, 0, sizeof(a));
		al = 0;
		memset(cp, 0, sizeof(cp));
		cl = 0;
	}
	;
};
char le[] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h' };
const int l = 8;
Node* root = null;

void copy(Node* root, Node* node, int index, char c)
{
	int k = root->al + 1;
	int j = 0;
	for (int i = 0; i < k; i++)
	{
		if (i == index)
		{
			node->a[node->al++] = c;
			continue;
		}
		node->a[node->al++] = root->a[j++];
	}
}

void buildTree(Node* root, int index, int n)
{
	if (index == n) return;
	for (int i = index; i >= 0; i--)
	{
		Node* node = new Node();
		copy(root, node, i, le[index]);
		root->cp[root->cl++] = node;
	}
	for (int i = 0; i < root->cl; i++)
		buildTree(root->cp[i], index + 1, n);
}
void blank(int n)
{
	for (int i = 0; i < n; i++)
		cout << " ";
}
void print(char a[], int l)
{
	cout << a[0];
	for (int i = 1; i < l; i++)
		cout << "," << a[i];

}
void dfs(Node* root, int n, int index, int bs)
{
	if (index + 1 == n)
	{
		blank(bs);
		cout << "writeln(";
		print(root->a, root->al);
		cout << ")" << endl;
		return;
	}
	for (int i = 0; i < root->cl; i++)
	{
		blank(bs);
		if (i == 0)
		{
			cout << "if ";
		}
		else if (i == root->cl - 1)
		{
			cout << "else ";
		}
		else
		{
			cout << "else if ";
		}
		if (i == 0)
		{
			cout << root->cp[i]->a[index] << " < " << root->cp[i]->a[index + 1]
					<< " " << "then";
		}
		else if (i != root->cl - 1)
		{
			cout << root->cp[i]->a[index - i] << " < "
					<< root->cp[i]->a[index + 1 - i] << " " << "then";
		}
		cout << endl;
		dfs(root->cp[i], n, index + 1, bs + 2);
	}
}

int main()
{
	freopen("C:\\Users\\zzzzz\\Desktop\\1.txt", "r", stdin);
	int caseNum = 0;
	cin >> caseNum;
	while (caseNum--)
	{
		int m;
		cin >> m;
		cout << "program sort(input,output);" << endl;
		cout << "var" << endl;
		print(le, m);
		cout << " : " << "integer;" << endl;
		cout << "begin" << endl;
		int bs = 2;
		blank(bs);
		cout << "readln(";
		print(le, m);
		cout << ");" << endl;
		int index = 0;
		root = new Node();
		root->a[root->al++] = le[index];
		index++;
		buildTree(root, index, m);
		//cout << root->cl << endl;
		if (m == 1)
		{
			blank(bs);
			cout << "writeln(a)" << endl;
		}
		else
		{
			dfs(root, m, 0, bs);
		}
		cout << "end." << endl;
		if (caseNum != 0)
		{
			cout << endl;
		}
	}

	return 0;
}