Add 0706-design-hashmap.c

Author: seinlin

c/0706-design-hashmap.c

@@ -0,0 +1,117 @@
+#define HASH_SIZE 1024
+
+typedef struct HashNode {
+    int key;
+    int value;
+    struct HashNode *next;
+} HashNode;
+
+typedef struct  {
+    HashNode *hash[HASH_SIZE];
+} MyHashMap;
+
+inline HashNode *NewHashNode(int key, int value) {
+    HashNode *h = (HashNode*)malloc(sizeof(HashNode));
+    h->key = key;
+    h->value = value;
+    h->next = NULL;
+    return h;
+}
+
+inline int KeyToIndex(int key) {
+    while (key < 0) key += HASH_SIZE;
+    return key % HASH_SIZE;
+}
+
+MyHashMap* myHashMapCreate() {
+    MyHashMap* h = (MyHashMap*)calloc(1, sizeof(MyHashMap));
+    return h;
+}
+
+void myHashMapPut(MyHashMap* obj, int key, int value) {
+    assert(obj);
+    HashNode **hash = &obj->hash[KeyToIndex(key)];
+    HashNode *h = *hash;
+    if (!*hash) {
+        *hash = NewHashNode(key, value);
+    } else if (h->key == key) {
+        h->value = value;
+        return;
+    } else {
+        while (h->next) {
+            h = h->next;
+            if (h->key == key) {
+                h->value = value;
+                return;
+            }
+        }
+        h->next = NewHashNode(key, value);
+    }
+}
+
+int myHashMapGet(MyHashMap* obj, int key) {
+    assert(obj);
+    HashNode* hash = obj->hash[KeyToIndex(key)];
+    while (hash) {
+        if (hash->key == key) {
+            return hash->value;
+        }
+        hash = hash->next;
+    }
+    return -1;
+}
+
+void myHashMapRemove(MyHashMap* obj, int key) {
+    assert(obj);
+    HashNode **head = &obj->hash[KeyToIndex(key)];
+    if (*head) {
+        HashNode *h = *head;
+        if (h->key == key) {
+            HashNode *tmp = *head;
+            *head = h->next;
+            free(tmp);
+            return;
+        } else {
+            HashNode *h_parent = h;
+            while(h) {
+                if (h->key == key) {
+                    h_parent->next = h->next;
+                    free(h);
+                    return;
+                }
+                h_parent = h;
+                h = h->next;
+            }
+        }
+    }
+    return;
+}
+
+void myHashMapFree(MyHashMap* obj) {
+    if(obj) {
+        HashNode* h;
+        HashNode *tmp;
+        for (int i = 0; i < HASH_SIZE; i++) {
+            h = obj->hash[i];
+            if(h) {
+                while (h != NULL) {
+                    tmp = h->next;
+                    free(h);
+                    h = tmp;
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Your MyHashMap struct will be instantiated and called as such:
+ * MyHashMap* obj = myHashMapCreate();
+ * myHashMapPut(obj, key, value);
+
+ * int param_2 = myHashMapGet(obj, key);
+
+ * myHashMapRemove(obj, key);
+
+ * myHashMapFree(obj);
+*/