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  1. #include<stdio.h>
  2. #include<stdlib.h>
  3. #include<pthread.h>
  4. int position[300]={0},col[100]={0},dig[300]={0},invdig[300]={0},count=0,check[100]={0},thread_count;
  5. pthread_t tid[100];
  6. pthread_mutex_t lock;
  7. struct Posi{
  8.     int x;
  9. 	int y;
  10. 	int n;
  11.         int p_col[100];
  12. 	int p_dig[300];
  13. 	int p_invdig[300];
  14. 	int p_position[300];
  15. 	int thread_id;
  16. };
  17. void nqueen(int n,int row,int n_position[],int n_col[],int n_dig[],int n_invdig[],int which,int x,int y){
  18. 	int i,j;
  19. 	if(x!=-1 && y!=-1){
  20. 		n_col[y]=1;
  21. 		n_dig[x-y+n]=1;
  22. 		n_invdig[x+y]=1;
  23. 		n_position[x]=y;
  24. 	}
  25. 	if(row==(n+1)){
  26. 	/*	for(i=1;i<=n;i++){
  27. 			for(j=1;j<=n;j++){
  28. 				if(n_position[i]==j)
  29. 					printf("o");
  30. 				else 
  31. 					printf("x");
  32. 			}
  33. 			printf("\n");
  34. 		}
  35. 		printf("=========================\n");*/
  36. 		pthread_mutex_lock(&lock);
  37. 		count++;
  38. 		pthread_mutex_unlock(&lock);
  39. 		return;
  40. 	}
  41. 	else if(check[row]==1){
  42. 		nqueen(n,row+1,n_position,n_col,n_dig,n_invdig,which,-1,-1);
  43. 	}
  44. 	else{		
  45. 		for(i=1;i<=n;i++){
  46. 			if(n_col[i]==0 && n_dig[row-i+n]==0 && n_invdig[i+row]==0){
  47. 				n_col[i]=1;
  48. 				n_dig[row-i+n]=1;
  49. 				n_invdig[i+row]=1;
  50. 				n_position[row]=i;
  51. 				nqueen(n,row+1,n_position,n_col,n_dig,n_invdig,which,-1,-1);
  52. 				n_col[i]=0;
  53. 				n_dig[row-i+n]=0;
  54. 				n_invdig[i+row]=0;
  55. 			}
  56. 		}
  57. 	}
  58. }
  59. void *parallel(void *k){
  60. 	struct Posi *get=(struct Posi*)k;
  61. 	nqueen(get->n,get->x+1,get->p_position,get->p_col,get->p_dig,get->p_invdig,get->thread_id,get->x,get->y);
  62. 	pthread_exit(NULL); 
  63. }
  64. int gotoparallel(int n){
  65. 	int i,j,k,rc;
  66. 	struct Posi pos[100];
  67. 	for(i=1;i<=n;i++){
  68. 		if(check[i]!=1){
  69. 			for(j=1;j<=n;j++){
  70. 				if(col[j]==0 && dig[i-j+n]==0 && invdig[j+i]==0){
  71. 					for(k=1;k<=2*n;k++){
  72. 						pos[thread_count].p_col[k]=col[k];
  73. 						pos[thread_count].p_dig[k]=dig[k];
  74. 						pos[thread_count].p_invdig[k]=invdig[k];
  75. 						pos[thread_count].p_position[k]=position[k];
  76. 					}
  77. 					pos[thread_count].x=i;
  78. 					pos[thread_count].y=j;
  79. 					pos[thread_count].n=n;
  80. 					pos[thread_count].thread_id=thread_count;
  81. 					rc=pthread_create(&tid[thread_count],NULL,parallel,(void*)&pos[thread_count]);
  82. 					if(rc){
  83. 						printf("ERROR; retrun for pthread_create is %d\n",rc);
  84. 						exit(-1);
  85. 					}
  86. 			/*		if(pthread_join(tid[thread_count],NULL)){
  87. 						perror("pthread_join");
  88. 						return 1;
  89. 					}*/
  90. 					thread_count++;
  91. 				}
  92. 			}
  93. 			break;
  94. 		}
  95. 	}
  96. 	for(i=0;i<thread_count;i++){
  97. 		if(pthread_join(tid[thread_count],NULL)){
  98. 			printf("thread join error\n");
  99. 		}
  100. 	}
  101. 	return 0;
  102. }
  103.  
  104. int main (){
  105. 	int n,m,x,y,i;
  106. 	thread_count=0;
  107. 	scanf("%d %d",&n,&m);
  108. 	for(i=0;i<m;i++){
  109. 		scanf("%d %d",&x,&y);
  110. 		x++;
  111. 		y++;
  112. 		col[y]=1;
  113. 		dig[x-y+n]=1;
  114. 		invdig[y+x]=1;
  115. 		check[x]=1;	
  116. 		position[x]=y;
  117. 	}
  118. 	gotoparallel(n);
  119. 	printf("count=%d\n",count);
  120. 	return 0;
  121. }
  122.  
Compilation error #stdin compilation error #stdout 0s 0KB
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stdin
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Standard input is empty
compilation info 
prog.cpp: In function ‘void nqueen(int, int, int*, int*, int*, int*, int, int, int)’:
prog.cpp:18:8: warning: unused variable ‘j’ [-Wunused-variable]
/home/eHPROz/cc0iQdyz.o: In function `gotoparallel(int)':
prog.cpp:(.text+0x2a7): undefined reference to `pthread_join'
prog.cpp:(.text+0x3b8): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
stdout
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Standard output is empty
https://ideone.com/HteU6a
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
public

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