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63 lines
1.2 KiB
63 lines
1.2 KiB
/**
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* File: simple_hash.dart
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* Created Time: 2023-06-25
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* Author: liuyuxin (gvenusleo@gmail.com)
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*/
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/* 加法哈希 */
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int addHash(String key) {
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int hash = 0;
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final int MODULUS = 1000000007;
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for (int i = 0; i < key.length; i++) {
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hash = (hash + key.codeUnitAt(i)) % MODULUS;
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}
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return hash;
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}
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/* 乘法哈希 */
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int mulHash(String key) {
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int hash = 0;
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final int MODULUS = 1000000007;
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for (int i = 0; i < key.length; i++) {
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hash = (31 * hash + key.codeUnitAt(i)) % MODULUS;
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}
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return hash;
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}
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/* 异或哈希 */
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int xorHash(String key) {
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int hash = 0;
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final int MODULUS = 1000000007;
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for (int i = 0; i < key.length; i++) {
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hash ^= key.codeUnitAt(i);
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}
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return hash & MODULUS;
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}
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/* 旋转哈希 */
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int rotHash(String key) {
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int hash = 0;
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final int MODULUS = 1000000007;
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for (int i = 0; i < key.length; i++) {
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hash = ((hash << 4) ^ (hash >> 28) ^ key.codeUnitAt(i)) % MODULUS;
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}
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return hash;
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}
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/* Dirver Code */
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void main() {
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String key = "Hello 算法";
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int hash = addHash(key);
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print("加法哈希值为 $hash");
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hash = mulHash(key);
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print("乘法哈希值为 $hash");
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hash = xorHash(key);
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print("异或哈希值为 $hash");
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hash = rotHash(key);
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print("旋转哈希值为 $hash");
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}
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