hello-algo/zh-hant/codes/cpp/chapter_searching/hashing_search.cpp

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/**
* File: hashing_search.cpp
* Created Time: 2022-11-25
* Author: krahets (krahets@163.com)
*/
#include "../utils/common.hpp"
/* 雜湊查詢(陣列) */
int hashingSearchArray(unordered_map<int, int> map, int target) {
// 雜湊表的 key: 目標元素value: 索引
// 若雜湊表中無此 key ,返回 -1
if (map.find(target) == map.end())
return -1;
return map[target];
}
/* 雜湊查詢(鏈結串列) */
ListNode *hashingSearchLinkedList(unordered_map<int, ListNode *> map, int target) {
// 雜湊表的 key: 目標節點值value: 節點物件
// 若雜湊表中無此 key ,返回 nullptr
if (map.find(target) == map.end())
return nullptr;
return map[target];
}
/* Driver Code */
int main() {
int target = 3;
/* 雜湊查詢(陣列) */
vector<int> nums = {1, 5, 3, 2, 4, 7, 5, 9, 10, 8};
// 初始化雜湊表
unordered_map<int, int> map;
for (int i = 0; i < nums.size(); i++) {
map[nums[i]] = i; // key: 元素value: 索引
}
int index = hashingSearchArray(map, target);
cout << "目標元素 3 的索引 = " << index << endl;
/* 雜湊查詢(鏈結串列) */
ListNode *head = vecToLinkedList(nums);
// 初始化雜湊表
unordered_map<int, ListNode *> map1;
while (head != nullptr) {
map1[head->val] = head; // key: 節點值value: 節點
head = head->next;
}
ListNode *node = hashingSearchLinkedList(map1, target);
cout << "目標節點值 3 的對應節點物件為 " << node << endl;
return 0;
}