fork download
copy 
  1. #include <iostream>
  2.  
  3. struct Node {
  4. 	int   val;
  5. 	Node* prev;
  6. 	Node* next;
  7.  
  8. 	Node( ) :
  9. 		val( 0 ),
  10. 		prev( NULL ),
  11. 		next( NULL ) {
  12. 	}
  13. };
  14.  
  15. void swap(Node * n1, Node * n2){
  16.     if(n1 == n2)
  17.         return;
  18.     if(n1 == 0 || n2 == 0){
  19.         std::cout << "\nPRIORITYQUEUE ERROR: Trying to swap with non-existent node\n";
  20.         return;
  21.     }
  22.  
  23.     Node * temp = new Node;
  24.  
  25.     temp->prev = n1->prev;
  26.     temp->next = n1->next;
  27.  
  28.     n1->prev = n2->prev;
  29.     n1->next = n2->next;
  30.  
  31.     n2->prev = temp->prev;
  32.     n2->next = temp->next;
  33.  
  34.     if(n1->next != 0)
  35.         n1->next->prev = n1;
  36.     if(n1->prev != 0)
  37.         n1->prev->next = n1;
  38.     if(n2->next != 0)
  39.         n2->next->prev = n2;
  40.     if(n2->prev != 0)
  41.         n2->prev->next = n2;
  42.  
  43.     delete temp;
  44.  
  45. }
  46.  
  47. void print( Node* r ) {
  48. 	Node* p = r->next;
  49. 	while( p != NULL ) {
  50. 		printf( "%d ", p->val );
  51. 		p = p->next;
  52. 	}
  53. }
  54.  
  55. Node* end( Node* r ) {
  56. 	Node* p = r;
  57. 	while( p->next != NULL ) {
  58. 		p = p->next;
  59. 	}
  60. 	return p;
  61. }
  62.  
  63. void print_reverse( Node* r ) {
  64. 	Node* p = r;
  65. 	while( p->prev != NULL ) {
  66. 		printf( "%d ", p->val );
  67. 		p = p->prev;
  68. 	}
  69. }
  70.  
  71. int main() {
  72. 	Node* r1 = new Node( );
  73. 	Node* r2 = new Node( );
  74. 	Node* p1 = r1; Node* p2 = r2;
  75. 	for( int i = 0; i < 10; ++i ) {
  76. 		p1->next = new Node( );
  77. 		p1->next->val = i;
  78. 		p1->next->prev = p1;
  79. 		p1 = p1->next;
  80. 	}
  81. 	for( int i = 0; i < 10; ++i ) {
  82. 		p2->next = new Node( );
  83. 		p2->next->val = 10 - i - 1;
  84. 		p2->next->prev = p2;
  85. 		p2 = p2->next;
  86. 	}
  87.  
  88. 	printf( "old r1  forward " );
  89. 	print( r1 );
  90. 	printf( "\n" );
  91.  
  92. 	printf( "old r1 backword " );
  93. 	print_reverse( end( r1 ) );
  94. 	printf( "\n" );
  95.  
  96. 	printf( "old r2  forward " );
  97. 	print( r2 );
  98. 	printf( "\n" );
  99.  
  100. 	printf( "old r2 backword " );
  101. 	print_reverse( end( r2 ) );
  102. 	printf( "\n" );
  103.  
  104. 	p1 = r1;
  105. 	while( p1->val != 3 ) { p1 = p1->next; }
  106.  
  107. 	p2 = r2;
  108. 	while( p2->val != 7 ) { p2 = p2->next; }
  109.  
  110. 	swap( p1, p2 );
  111.  
  112. 	printf( "new r1  forward " );
  113. 	print( r1 );
  114. 	printf( "\n" );
  115.  
  116. 	printf( "new r1 backword " );
  117. 	print_reverse( end( r1 ) );
  118. 	printf( "\n" );
  119.  
  120. 	printf( "new r2  forward " );
  121. 	print( r2 );
  122. 	printf( "\n" );
  123.  
  124. 	printf( "new r2 backword " );
  125. 	print_reverse( end( r2 ) );
  126. 	printf( "\n" );
  127.  
  128. 	return 0;
  129. }
Success #stdin #stdout 0s 2860KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
old r1  forward 0 1 2 3 4 5 6 7 8 9 
old r1 backword 9 8 7 6 5 4 3 2 1 0 
old r2  forward 9 8 7 6 5 4 3 2 1 0 
old r2 backword 0 1 2 3 4 5 6 7 8 9 
new r1  forward 0 1 2 7 4 5 6 7 8 9 
new r1 backword 9 8 7 6 5 4 7 2 1 0 
new r2  forward 9 8 3 6 5 4 3 2 1 0 
new r2 backword 0 1 2 3 4 5 6 3 8 9
https://ideone.com/wsd3OX
language:
C++ 4.3.2 (gcc-4.3.2)
created:
9 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!