hello-algo/codes/cpp/chapter_searching/hashing_search.cpp
Yudong Jin 19a4ccd86a Add cpp codes for the chapter
computational complexity, sorting, searching.
2022-11-27 04:20:30 +08:00

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/*
* File: hashing_search.cpp
* Created Time: 2022-11-25
* Author: Krahets (krahets@163.com)
*/
#include "../include/include.hpp"
/* 哈希查找(数组) */
int hashingSearch(unordered_map<int, int> map, int target) {
// 哈希表的 key: 目标元素value: 索引
// 若哈希表中无此 key ,返回 -1
if (map.find(target) == map.end())
return -1;
return map[target];
}
/* 哈希查找(链表) */
ListNode* hashingSearch1(unordered_map<int, ListNode*> map, int target) {
// 哈希表的 key: 目标结点值value: 结点对象
// 若哈希表中无此 key ,返回 nullptr
if (map.find(target) == map.end())
return nullptr;
return map[target];
}
/* Driver Code */
int main() {
int target = 3;
/* 哈希查找(数组) */
vector<int> nums = { 1, 5, 3, 2, 4, 7, 5, 9, 10, 8 };
// 初始化哈希表
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 = hashingSearch(map, target);
cout << "目标元素 3 的索引 = " << index << endl;
/* 哈希查找(链表) */
ListNode* head = vectorToLinkedList(nums);
// 初始化哈希表
unordered_map<int, ListNode*> map1;
while (head != nullptr) {
map1[head->val] = head; // key: 结点值value: 结点
head = head->next;
}
ListNode* node = hashingSearch1(map1, target);
cout << "目标结点值 3 的对应结点对象为 " << node << endl;
return 0;
}