案例讲解-数组实现字典树

看了POJ上的一道题目，大致讲的是给出一方语言A词语所对应的另一方语言B的含义，然后给出B的一些词语，找到A所对应的翻译。显而易见，每个词语逻辑上可以看成是字典树，笔者用数组来实现字典树，具体代码如下，可作参考~

#ifndef  _CRT_SECURE_NO_WARNINGS
#define  _CRT_SECURE_NO_WARNINGS
#endif

#include
#include
#define   MAX_LENTH   10

typedef  struct  DictionTree{
	int   childID[26];      //每个字母后面仅有26中可能，抽象成一种数据结构
	char  data[MAX_LENTH + 1];         //对应的含义
}DictionTree;

DictionTree  Node[200000];  //要分配的足够多
int          pNodeParent = 0;
int          g_NodeCount = 1;
void init();
void createDictionTree(char*engWod, int engLenth, char*foreign, int foreignLen);
int  search(char*word, int wordLen);


void init()
{
	memset(Node, -1, sizeof(Node));
}

void createDictionTree(char*engWod, int engLenth, char*foreign, int foreignLen)
{
	int tempParent = 0;
	for (int i = 0; i < foreignLen; i++)
	{
		int childIndex = foreign[i] - 'a';
		if (Node[tempParent].childID[childIndex] == -1)//如果说之前没有使用的话
		{
			Node[tempParent].childID[childIndex] = g_NodeCount;
			tempParent = g_NodeCount;
			g_NodeCount++;
		}
		else
		{
			tempParent = Node[tempParent].childID[childIndex];
		}
	}
	int index;
	for (index = 0; index < engLenth; index++)
	{
		Node[tempParent].data[index] = engWod[index];
	}
	Node[tempParent].data[index] = '\0';
}

int  search(char*word, int wordLen)
{
	int tempParent = 0;
	for (int i = 0; i < wordLen; i++)
	{
		int childIndex = word[i] - 'a';
		if (Node[tempParent].childID[childIndex] == -1)
		{
			return -1;   //表示失败
		}
		else
		{
			tempParent = Node[tempParent].childID[childIndex];
		}

	}
	return tempParent;
}

int main()
{
	char engWord[MAX_LENTH+1];//前面的单词
	char foreignMeaning[MAX_LENTH+1]; //后面的含义
	char wordBeLookUp[MAX_LENTH];
	freopen("input.txt", "r", stdin);
	char input[2 * MAX_LENTH + 1];
	init();

	while (true)
	{
		gets(input);
		if (input[0] != '\0')
		{
			int i;
			for (i = 0; input[i] != ' '; i++)
			{
				engWord[i] = input[i];
			}
			engWord[i] = '\0';
			int j;
			int index = 0;
			for (j = i + 1; input[j] != '\0'; j++)
			{
				foreignMeaning[index++] = input[j];
			}
			foreignMeaning[index] = '\0';
			createDictionTree(engWord, i, foreignMeaning, index);
		}
		else
		{
			break;
		}
	}

	while (true)
	{
		if (NULL == gets(wordBeLookUp))
		{
			break;
		}
		if (wordBeLookUp[0] != '\0')
		{
			int result = search(wordBeLookUp, strlen(wordBeLookUp));
			if (result == -1)
			{
				printf("eh\n");
			}
			else
			{
				for (int j = 0; Node[result].data[j] != '\0'; j++)
				{
					printf("%c", Node[result].data[j]);
				}
				printf("\n");
			}
		}
		else
		{
			break;
		}
	}

	return 0;

}

其中输入input.txt内容如下：

dog ogday
cat atcay
pig igpay
froot ootfray
loops oopslay
aaaaa bbbbb
xxxxx yyyyy
aaaba aaaca
akghd bhaalf


atcay
ittenkay
oopslay
yyyyy