杭电 hdu 1305 Immediate Decodability

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写代码的安徒生

最新推荐文章于 2022-02-25 19:38:17 发布

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分类专栏：字典树文章标签： insert struct c

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本文讨论了如何在程序中实现立即解码的集合判断，并提供了代码示例。文章详细介绍了数据结构和算法的应用，包括节点结构、插入操作和回退机制，确保集合的立即解码特性。

/* THE PROGRAM IS MADE BY PYY */
/*----------------------------------------------------------------------------//
Copyright (c) 2011 panyanyany All rights reserved.

URL   : http://acm.hdu.edu.cn/showproblem.php?pid=1305
Name  : 1305 Immediate Decodability

Date  : Wednesday, August 24, 2011
Time Stage : half an hour

Result:
4486760	2011-08-24 21:16:51	Accepted	1305
0MS	240K	1929 B
C++	pyy


Test Data:


Review:

//----------------------------------------------------------------------------*/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define max(a, b) (((a) > (b)) ? (a) : (b))
#define min(a, b) (((a) < (b)) ? (a) : (b))

#define infinity    0x0f0f0f0f
#define minus_inf    0x80808080

#define MAXSIZE	1009

typedef struct tagNODE {
	int cnt ;
	struct tagNODE * child[2] ;
} NODE ;

char str[22] ;

int can ;
int stkPtr ;

NODE * stack[MAXSIZE] ;
NODE * tmp, * newNode ;

#define root stack[0]

void insert (char *patn)
{
	int i, j ;
	int len = strlen (patn) ;
	tmp = root ;
	for (i = 0 ; i < len - 1 ; ++i)
	{
		j = patn[i] - '0' ;
		if (!tmp->child[j])
		{
			newNode = (NODE *) calloc (1, sizeof (NODE)) ;
			stack[stkPtr++] = newNode ;
			tmp->child[j] = newNode ;
		}
		tmp = tmp->child[j] ;
		if (tmp->cnt)
			can = 0 ;
	}
	// 我用的判断方法貌似不太美观，看了下别人的代码，
	// 通过判断下一层的孩子指针是否存在，可以达到同样的效果
	j = patn[i] - '0' ;
	if (tmp->child[j])
	{
		can = 0 ;
	}
	else
	{
		newNode = (NODE *) calloc (1, sizeof (NODE)) ;
		stack[stkPtr++] = newNode ;
		tmp->child[j] = newNode ;
	}
	tmp = tmp->child[j] ;
	++tmp->cnt ;
}

void recycle ()
{
	while (stkPtr)
		free (stack[--stkPtr]) ;
}

int main ()
{
	int i, j, tmp, tcase ;
	tcase = 0 ;
	while (scanf ("%s", str) != EOF)
	{
		can = 1 ;
		stkPtr = 1 ;
		root = (NODE *) calloc (1, sizeof (NODE)) ;
		insert (str) ;
		while (scanf ("%s", str), *str != '9')
			insert (str) ;
		if (can)
			printf ("Set %d is immediately decodable\n", ++tcase) ;
		else
			printf ("Set %d is not immediately decodable\n", ++tcase) ;
		
		recycle () ;
	}
	return 0 ;
}