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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct Cell {
  5. 	long val;
  6. 	struct Cell *prev;
  7. 	struct Cell *next;
  8. };
  9.  
  10. class DoubleLinkedList {
  11. public:
  12. 	DoubleLinkedList() {
  13. 		first = NULL;
  14. 		last = NULL;
  15. 	}
  16. 	void ins(long x) {
  17. 		struct Cell *c = new Cell;
  18. 		c->val = x;
  19. 		c->prev = NULL;
  20. 		c->next = first;
  21.         if (first != NULL) { first->prev = c; }
  22. 		first = c;
  23.         if (last == NULL) {
  24.             last = c;
  25.         }
  26. 	}
  27. 	void del(long x) {
  28. 		struct Cell *p = first;
  29. 		struct Cell *pPrev;
  30. 		struct Cell *pNext;
  31. 		while(p->val != x) {
  32. 			p = p->next;
  33.             if (!p) { return; }
  34. 		}
  35.  
  36. 		pPrev = p->prev;
  37. 		pNext = p->next;
  38.         if (pNext) { pNext->prev = pPrev; }
  39. 		if (pPrev) { pPrev->next = pNext; }
  40. 		if (p == first) {
  41. 			first = pNext;
  42. 		}
  43. 		if (p == last) {
  44. 			last = pPrev;
  45. 		}
  46. 		delete p;
  47. 	}
  48. 	void delFirst() {
  49. 		struct Cell *p = first->next;
  50.         if (p) { p->prev=NULL; }
  51.         if (first == last) {
  52.             last = NULL;
  53.         }
  54. 		delete first;
  55. 		first = p;
  56. 	}
  57. 	void delLast() {
  58. 		struct Cell *p = last->prev;
  59. 		if (p) { p->next = NULL; }
  60.         if (last == first) {
  61.             first = NULL;
  62.         }
  63. 		delete last;
  64. 		last = p;
  65. 	}
  66. 	void printValues() {
  67. 		struct Cell *p = first;
  68.  
  69.         if (p) {
  70.             cout << p->val;
  71.             p = p->next;
  72.         }
  73. 		while (p) {
  74. 			cout << " ";
  75.             cout << p->val;
  76.             p = p->next;
  77. 		}
  78.         cout << endl;
  79. 	}
  80. private:
  81. 	struct Cell *first;
  82. 	struct Cell *last;
  83. };
  84.  
  85. int main()
  86. {
  87. 	long n, value;
  88. 	string cmd;
  89. 	DoubleLinkedList dll;
  90.  
  91. 	cin >> n;
  92. 	for (long i=0; i<n; i++) {
  93. 		cin>> cmd;
  94. 		if (cmd == "insert") {
  95.             cin >> value;
  96.             dll.ins(value);
  97.             continue;
  98.         }
  99. 		else if (cmd == "delete") {
  100.             cin >> value;
  101.             dll.del(value);
  102.             continue;
  103.         }
  104. 		else if (cmd == "deleteFirst") { dll.delFirst(); continue; }
  105. 		else if (cmd == "deleteLast") { dll.delLast(); }
  106. 	}
  107.  
  108. 	// outpur values in ddl
  109.     dll.printValues();
  110.  
  111. 	return 0;
  112. }
Success #stdin #stdout 0s 3476KB
comments (?)
stdin
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9
insert 5
insert 2
insert 3
insert 1
delete 3
insert 6
delete 5
deleteFirst
deleteLast
stdout
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1
https://ideone.com/0DrYdb
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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