如何在C中找到矩阵中元素的所有唯一位置集？

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

#define MAX_SIZE 100

// 定义哈希表节点结构
typedef struct Node {
    int value;
    int* positions;
    int count;
    struct Node* next;
} Node;

// 创建哈希表节点
Node* createNode(int value, int position) {
    Node* node = (Node*)malloc(sizeof(Node));
    node->value = value;
    node->positions = (int*)malloc(sizeof(int) * MAX_SIZE);
    node->positions[0] = position;
    node->count = 1;
    node->next = NULL;
    return node;
}

// 向哈希表中插入节点
void insertNode(Node** hashTable, int value, int position) {
    int index = abs(value) % MAX_SIZE;
    Node* node = hashTable[index];
    if (node == NULL) {
        hashTable[index] = createNode(value, position);
    } else {
        while (node->next != NULL) {
            if (node->value == value) {
                node->positions[node->count++] = position;
                return;
            }
            node = node->next;
        }
        if (node->value == value) {
            node->positions[node->count++] = position;
        } else {
            node->next = createNode(value, position);
        }
    }
}

// 打印矩阵中元素的唯一位置集
void printUniquePositions(Node** hashTable) {
    for (int i = 0; i < MAX_SIZE; i++) {
        Node* node = hashTable[i];
        while (node != NULL) {
            printf("元素 %d 的位置集合：", node->value);
            for (int j = 0; j < node->count; j++) {
                printf("%d ", node->positions[j]);
            }
            printf("\n");
            node = node->next;
        }
    }
}

int main() {
    int matrix[3][3] = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };

    // 创建哈希表
    Node** hashTable = (Node**)malloc(sizeof(Node*) * MAX_SIZE);
    for (int i = 0; i < MAX_SIZE; i++) {
        hashTable[i] = NULL;
    }

    // 遍历矩阵，插入哈希表
    int position = 0;
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            insertNode(hashTable, matrix[i][j], position++);
        }
    }

    // 打印矩阵中元素的唯一位置集
    printUniquePositions(hashTable);

    // 释放哈希表内存
    for (int i = 0; i < MAX_SIZE; i++) {
        Node* node = hashTable[i];
        while (node != NULL) {
            Node* temp = node;
            node = node->next;
            free(temp->positions);
            free(temp);
        }
    }
    free(hashTable);

    return 0;
}