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Add the codes of hashmap (#553)

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of chaining and open addressing
This commit is contained in:
Yudong Jin
2023-06-14 02:01:06 +08:00
committed by GitHub
parent d3e597af94
commit 9563965a20
27 changed files with 1280 additions and 207 deletions
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30
codes/dart/chapter_hashing/array_hash_map.dart
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@ -4,16 +4,16 @@
* Author: liuyuxin (gvenusleo@gmail.com)
*/
/* 键值对 int -> String */
class Entry {
/* 键值对 */
class Pair {
int key;
String val;
Entry(this.key, this.val);
Pair(this.key, this.val);
}
/* 基于数组简易实现的哈希表 */
class ArrayHashMap {
late List<Entry?> _buckets;
late List<Pair?> _buckets;
ArrayHashMap() {
// 初始化数组，包含 100 个桶
@ -29,7 +29,7 @@ class ArrayHashMap {
/* 查询操作 */
String? get(int key) {
final int index = _hashFunc(key);
final Entry? pair = _buckets[index];
final Pair? pair = _buckets[index];
if (pair == null) {
return null;
}
@ -38,7 +38,7 @@ class ArrayHashMap {
/* 添加操作 */
void put(int key, String val) {
final Entry pair = Entry(key, val);
final Pair pair = Pair(key, val);
final int index = _hashFunc(key);
_buckets[index] = pair;
}
@ -50,20 +50,20 @@ class ArrayHashMap {
}
/* 获取所有键值对 */
List<Entry> entrySet() {
List<Entry> entrySet = [];
for (final Entry? pair in _buckets) {
List<Pair> pairSet() {
List<Pair> pairSet = [];
for (final Pair? pair in _buckets) {
if (pair != null) {
entrySet.add(pair);
pairSet.add(pair);
}
}
return entrySet;
return pairSet;
}
/* 获取所有键 */
List<int> keySet() {
List<int> keySet = [];
for (final Entry? pair in _buckets) {
for (final Pair? pair in _buckets) {
if (pair != null) {
keySet.add(pair.key);
}
@ -74,7 +74,7 @@ class ArrayHashMap {
/* 获取所有值 */
List<String> values() {
List<String> valueSet = [];
for (final Entry? pair in _buckets) {
for (final Pair? pair in _buckets) {
if (pair != null) {
valueSet.add(pair.val);
}
@ -84,7 +84,7 @@ class ArrayHashMap {
/* 打印哈希表 */
void printHashMap() {
for (final Entry kv in entrySet()) {
for (final Pair kv in pairSet()) {
print("${kv.key} -> ${kv.val}");
}
}
@ -118,7 +118,7 @@ void main() {
/* 遍历哈希表 */
print("\n遍历键值对 Key->Value");
map.entrySet().forEach((kv) => print("${kv.key} -> ${kv.val}"));
map.pairSet().forEach((kv) => print("${kv.key} -> ${kv.val}"));
print("\n单独遍历键 Key");
map.keySet().forEach((key) => print("$key"));
print("\n单独遍历值 Value");