Infa10M/LAST2.cpp.txt at master · vlapugb/Infa10M · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
#include <iostream>
#include <string>
using namespace std;
struct Node {
	int value;
	Node* next, *prev;
};
struct deque {
	Node* head = nullptr;
	Node* tail = nullptr;
	int counter = 0;
	void push_back(int nummer) {
		Node* element = new Node;
		element->value = nummer;
		counter++;
		if (!head) {
			head = element;
			tail = head;
		}
		else {
			element->prev = tail;
			tail->next = element;
			tail = element;
		}
	}
	void push_front(int nummer) {
		Node* element = new Node;
		element->value = nummer;
		counter++;
		if (!head) {
			head = element;
			tail = head;
		}
		else {
			element->next = head;
			head->prev = element;
			head = element;
		}
	}
	void pop_back() {
		if (counter != 0) {
			cout << tail->value << endl;
			if (counter > 1) {
				Node* element = tail;
				tail = tail->prev;
				tail->next = nullptr;
				delete element;
				counter--;
			}
			else {
				head = tail = 0;
				counter--;
			}
		}
		else cout << "error" << endl;
	}
	void pop_front() {
		if (counter != 0) {
			cout << head->value << endl;
			if (head->next) {
				Node* element = head;
				head = head->next;
				head->prev = nullptr;
				delete element;
				counter--;
			}
			else if (head == tail) {
				head->next = nullptr;
				head = nullptr;
				delete head;
				counter = 0;
			}
		}
		else cout << "error" << endl;
	}
	void back() {
		if (counter != 0)cout << tail->value << endl;
		else cout << "error" << endl;
	}
	void front() {
		if (counter != 0)cout << head->value << endl;
		else cout << "error" << endl;
	}
	void size() {
		cout << counter << endl;
	}
	void clear() {
		counter = 0;
		while (head)
		{
			tail = head->next;
			delete head;
			head = tail;
		}
	}
	void exit(){}
};
int main()
{
	deque deq;
	string str;
	while (cin >> str)
	{
		if (str == "push_front")
		{
			int num;
			cin >> num;
			deq.push_front(num);
		}
		if (str == "push_back")
		{
			int num;
			cin >> num;
			deq.push_back(num);
		}
		if (str == "pop_front")deq.pop_front();
		if (str == "pop_back")deq.pop_back();
		if (str == "clear")deq.clear();
		if (str == "size")deq.size();
		if (str == "front")deq.front();
		if (str == "back")deq.back();
		if (str == "exit") {
			deq.exit();
			break;
		}
	}
	return 0;
}