feat: Chaining hash table

hash-table.c

@@ -0,0 +1,134 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <time.h>
+
+#define TABLE_SIZE 10
+
+struct Node {
+    char key[48];
+    int value;
+    struct Node *next;
+};
+
+long long hash_function(char *key) {
+    long long hash = 0;
+    for (int i=0; i<strlen(key); i++){
+        hash = ((hash * 33) + key[i]) % TABLE_SIZE;
+    }
+    return hash ;
+}
+
+void insert(struct Node **table, char *key, int value) {
+    long long hash = hash_function(key);
+
+    printf("Hash: %lli\n", hash);
+
+    struct Node *node = malloc(sizeof(struct Node));
+    struct Node *temp, *past;
+    strcpy(node->key, key);
+    node->value = value;
+    node->next = NULL;
+
+    if (table[hash] == NULL){
+        table[hash] = node;
+        printf("Create.\n");
+    } else {
+        printf("Add.\n");
+        temp = table[hash];
+        past = NULL;
+        while(temp != NULL){
+            assert(temp->key != key);
+            printf("%s -> ", temp->key);
+            past = temp;
+            temp = temp->next;
+        }
+        printf("\n");
+        past->next = node;
+    }
+}
+
+void long_to_str(long long num, char *s, int length) {
+    int temp;
+    for (int i=length-1; i>=0; i--) {
+        temp = num % 10;
+        num /= 10;
+        s[i] = (char)(temp + 48);
+    }
+}
+
+int search(struct Node **table, char *key) {
+    long long hash = hash_function(key);
+    struct Node *temp, *past;
+
+    if (table[hash] == NULL){
+        return -1;
+    } else {
+        temp = table[hash];
+        past = NULL;
+
+        while(temp != NULL){
+            // printf("%s - %s\n", temp->key, key);
+            if (strcmp(temp->key, key) == 0){
+                return temp->value;
+            }
+            past = temp;
+            temp = temp->next;
+        }
+        return -1;
+    }
+}
+
+void update(struct Node **table, char *key, int value) {
+    long long hash = hash_function(key);
+    struct Node *temp, *past;
+
+    temp = table[hash];
+    past = NULL;
+    while(temp != NULL){
+        if (strcmp(temp->key, key) == 0){
+            temp->value = value;
+            break;
+        }
+        past = temp;
+        temp = temp->next;
+    }
+}
+
+int main(){
+    struct Node ** table;      // pointer to pointer
+    int size;
+    srand(time(NULL));
+
+    table = malloc(TABLE_SIZE * sizeof(struct Node*));
+    for (int i=0; i<TABLE_SIZE; i++){
+        table[i] = NULL;
+    }
+
+    long long a = 1234567890;
+    char s[21];
+    for (int i=0; i<50; i++){
+        a = (long long)rand();
+        printf("%lli\n", a);
+        long_to_str(a, s, 20);
+        printf("%s\n", s);
+        insert(table, s, i);
+        printf("\n");
+    }
+
+    int ans;
+    while (1) {
+        printf("> ");
+        scanf("%lli", &a);
+        printf("HERE\n");
+        long_to_str(a, s, 20);
+        printf("HERE\n");
+
+        update(table, s, 100);
+        ans = search(table, s);
+        printf("%d\n\n", ans);
+    }
+    // long long a = hash_function("9999999999999");
+    // printf("%lli\n", a);
+}