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  1. #include <stdio.h>
  2. #include <string.h>
  3. #include <stdlib.h>
  4.  
  5. #define LEN 128
  6. #define MAX 128
  7.  
  8. int main(void) {
  9. 	struct {
  10. 		int upcount;
  11. 		int downcount;
  12. 		int up[100];
  13. 		int down[100];
  14. 	} alphabet[26];
  15. 	for(int i=0;i<26;i++)
  16. 		alphabet[i].upcount=alphabet[i].downcount=0;
  17. 	char line[LEN];
  18. 	while(fgets(line,LEN,stdin)!=NULL)
  19. 	{
  20. 		int len=strlen(line);
  21. 		if(line[len-1]=='\n')
  22. 			line[--len]=0;
  23. 		char aa, bb;
  24. 		sscanf(line, "Step %c must be finished before step %c can begin.", &aa, &bb);
  25. 		int a=aa-'A';
  26. 		int b=bb-'A';
  27. 		alphabet[a].down[alphabet[a].downcount++] = b;
  28. 		alphabet[b].up[alphabet[b].upcount++] = a;
  29. 	}
  30.  
  31. 	int top;
  32. 	for(int i=0;i<26;i++)
  33. 		if(alphabet[i].upcount==0)
  34. 			top=i;
  35. 	int bottom;
  36. 	for(int i=0;i<26;i++)
  37. 		if(alphabet[i].downcount==0)
  38. 			bottom=i;	
  39. 	int available[26];
  40. 	for(int i=0;i<26;i++)
  41. 		available[i]=0;
  42.  
  43.  
  44. 	int solution[100];
  45. 	int k=0;
  46. 	int current=top;
  47.  
  48. 	int flag=0;
  49. 	while(1)
  50. 	{
  51. 		for(int i=0;i<alphabet[current].downcount;i++)
  52. 			available[alphabet[current].down[i]]=1;
  53.  
  54. 		for(int i=0;i<26;i++)
  55. 		{
  56. 			if(available[i])
  57. 			{
  58. 				solution[k++]=i;
  59. 				current=i;
  60. 				available[i]=0;
  61. 				break;
  62. 			}
  63. 			else {
  64. 				flag=1;
  65. 			}
  66. 		}
  67. 		if(flag) break;
  68.  
  69. 	}
  70.  
  71. 	solution[k]=0;
  72. 	for(int i=0;i<k;i++)
  73. 		printf("%c",solution[i]+'A');
  74. 	return 0;
  75. }
  76.  
Success #stdin #stdout 0.01s 5292KB
comments (?)
stdin
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Step U must be finished before step A can begin.
Step F must be finished before step Z can begin.
Step B must be finished before step J can begin.
Step O must be finished before step R can begin.
Step H must be finished before step S can begin.
Step T must be finished before step R can begin.
Step L must be finished before step W can begin.
Step M must be finished before step I can begin.
Step Q must be finished before step K can begin.
Step Z must be finished before step V can begin.
Step C must be finished before step E can begin.
Step W must be finished before step I can begin.
Step K must be finished before step S can begin.
Step I must be finished before step Y can begin.
Step P must be finished before step V can begin.
Step V must be finished before step X can begin.
Step R must be finished before step E can begin.
Step N must be finished before step E can begin.
Step X must be finished before step J can begin.
Step A must be finished before step J can begin.
Step S must be finished before step G can begin.
Step J must be finished before step E can begin.
Step Y must be finished before step E can begin.
Step D must be finished before step G can begin.
Step E must be finished before step G can begin.
Step K must be finished before step N can begin.
Step B must be finished before step I can begin.
Step X must be finished before step S can begin.
Step V must be finished before step S can begin.
Step U must be finished before step L can begin.
Step N must be finished before step G can begin.
Step O must be finished before step L can begin.
Step X must be finished before step E can begin.
Step V must be finished before step E can begin.
Step Y must be finished before step G can begin.
Step A must be finished before step Y can begin.
Step M must be finished before step E can begin.
Step F must be finished before step Q can begin.
Step F must be finished before step X can begin.
Step L must be finished before step C can begin.
Step T must be finished before step L can begin.
Step B must be finished before step C can begin.
Step Q must be finished before step N can begin.
Step T must be finished before step G can begin.
Step R must be finished before step D can begin.
Step I must be finished before step A can begin.
Step B must be finished before step M can begin.
Step H must be finished before step A can begin.
Step F must be finished before step K can begin.
Step U must be finished before step F can begin.
Step R must be finished before step A can begin.
Step J must be finished before step D can begin.
Step V must be finished before step Y can begin.
Step F must be finished before step J can begin.
Step C must be finished before step K can begin.
Step M must be finished before step C can begin.
Step F must be finished before step E can begin.
Step I must be finished before step E can begin.
Step T must be finished before step A can begin.
Step J must be finished before step Y can begin.
Step R must be finished before step X can begin.
Step W must be finished before step S can begin.
Step V must be finished before step R can begin.
Step U must be finished before step V can begin.
Step C must be finished before step V can begin.
Step F must be finished before step Y can begin.
Step R must be finished before step G can begin.
Step W must be finished before step N can begin.
Step H must be finished before step N can begin.
Step H must be finished before step Y can begin.
Step B must be finished before step W can begin.
Step M must be finished before step Z can begin.
Step X must be finished before step A can begin.
Step A must be finished before step G can begin.
Step N must be finished before step A can begin.
Step H must be finished before step J can begin.
Step B must be finished before step O can begin.
Step W must be finished before step A can begin.
Step P must be finished before step N can begin.
Step Z must be finished before step G can begin.
Step W must be finished before step D can begin.
Step D must be finished before step E can begin.
Step W must be finished before step J can begin.
Step N must be finished before step D can begin.
Step C must be finished before step J can begin.
Step B must be finished before step Y can begin.
Step F must be finished before step P can begin.
Step L must be finished before step P can begin.
Step X must be finished before step G can begin.
Step R must be finished before step Y can begin.
Step K must be finished before step A can begin.
Step M must be finished before step Y can begin.
Step W must be finished before step Y can begin.
Step F must be finished before step I can begin.
Step L must be finished before step X can begin.
Step R must be finished before step J can begin.
Step V must be finished before step J can begin.
Step V must be finished before step D can begin.
Step H must be finished before step C can begin.
Step O must be finished before step G can begin.
Step P must be finished before step R can begin.
stdout
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https://ideone.com/UQdA1L
language:
C (gcc 8.3)
created:
30 days ago
visibility:
public

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