团体程序设计天梯赛-练习集 L2-002 链表去重

题目链接

特点：采用Hash表

#include<iostream>
#include<unordered_map>
#include<map>
#include<string>
#include<vector>
using namespace std;

struct ListNode {
    
	string addr;
	string next;
	int data;
};
int f_abs(int x) {
    
	if (x > 0)	return x;
	return -x;
}
int main() {
    
	unordered_map<string, ListNode> LinkList;		//Hash表，存放原始链表
	vector<ListNode> Deleted;								//存放删除的链表节点
	map<int, int> nums;								//标记这个数是否存在
	string head;
	int n;
	cin >> head >> n;
	string addr, next;
	int data;
	int cur = 0;
	for (int i = 0; i < n; i++) {
    
		cin >> addr >> data >> next;
		LinkList[addr].addr = addr;
		LinkList[addr].data = data;
		LinkList[addr].next = next;
	}
	LinkList["-1"];		//address=-1作为迭代的终止条件
	string pre_node = head;
	string node = LinkList[head].next;
	nums[f_abs(LinkList[pre_node].data)] = 1;		//先存放头节点的数
	while (node!= "-1") {
    
		int x = f_abs(LinkList[node].data);
		nums[x]++;
		if (nums[x]>1) {
    							//这个数之前出现过
			if (cur > 0) {
    					//被删除节点链表的节点的前一个节点要特殊处理，即更改next值
				Deleted[cur - 1].next = node;
			}
			Deleted.push_back({
     node, "-1", LinkList[node].data });		//插入的节点next赋值为-1
			cur++;
			LinkList[pre_node].next = LinkList[node].next;
			node = LinkList[node].next;
		}
		else {
    
			pre_node = node;
			node = LinkList[node].next;
		}
	}
	//cout << endl;
	node = head;
	while (node != "-1") {
    
		cout << node << " " << LinkList[node].data << " " << LinkList[node].next<<endl;
		node = LinkList[node].next;
	}
	//cout << endl; 输出删除节点
	for (ListNode x : Deleted) {
    
		cout << x.addr << " " << x.data << " " << x.next << endl;
	}

	return 0;
}