C语言tire树词频统计

Trie树（又称字典树、前缀树）是一种数据结构，常用于字符串的存储和查找。在统计词频时，我们可以使用Trie树来进行高效的统计。

具体的实现步骤如下：

1. 定义Trie树节点结构体，并初始化根节点。

#define ALPHABET_SIZE 26

struct TrieNode {
    struct TrieNode* children[ALPHABET_SIZE];
    bool isEndOfWord;
    int frequency;
};

struct TrieNode* createNode() {
    struct TrieNode* node = (struct TrieNode*)malloc(sizeof(struct TrieNode));
    for (int i = 0; i < ALPHABET_SIZE; i++) {
        node->children[i] = NULL;
    }
    node->isEndOfWord = false;
    node->frequency = 0;
    return node;
}

struct TrieNode* root = createNode();

2. 插入单词。

void insertWord(char* word) {
    struct TrieNode* node = root;
    for (int i = 0; word[i] != '\0'; i++) {
        int index = word[i] - 'a';
        if (node->children[index] == NULL) {
            node->children[index] = createNode();
        }
        node = node->children[index];
    }
    node->isEndOfWord = true;
    node->frequency++;
}

3. 统计单词出现次数。

void countWords(struct TrieNode* node, char* buffer, int depth) {
    if (node->isEndOfWord) {
        buffer[depth] = '\0';
        printf("%s : %d\n", buffer, node->frequency);
    }
    for (int i = 0; i < ALPHABET_SIZE; i++) {
        if (node->children[i] != NULL) {
            buffer[depth] = i + 'a';
            countWords(node->children[i], buffer, depth + 1);
        }
    }
}

void printWords() {
    char buffer[MAX_WORD_LENGTH];
    countWords(root, buffer, 0);
}

4. 读取文本文件，并进行词频统计。

#define MAX_LINE_LENGTH 1024

void countWordsFromFile(char* fileName) {
    FILE* fp = fopen(fileName, "r");
    if (fp == NULL) {
        printf("Failed to open file: %s\n", fileName);
        return;
    }
    char line[MAX_LINE_LENGTH];
    while (fgets(line, MAX_LINE_LENGTH, fp) != NULL) {
        char* word = strtok(line, " \n\t\r");
        while (word != NULL) {
            insertWord(word);
            word = strtok(NULL, " \n\t\r");
        }
    }
    fclose(fp);
}

使用以上代码即可对文本文件中的单词进行词频统计。