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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. int main() {
  4. 	int t;
  5. 	cin>>t;
  6. 	while(t--){
  7. 		unordered_map<string,int> vis;
  8. 		string s,f;
  9. 		int n;
  10. 		cin>>s>>f;
  11. 		n=s.length();
  12. 		int pos = 0;
  13. 		for(int i = 0 ; i<s.length(); i++){
  14. 			if(s[i]=='_'){
  15. 				pos = i;
  16. 				break;
  17. 			}
  18. 		}
  19. 		queue<pair<string,int> > q;
  20. 		q.push({s,pos});
  21. 		vis[s]=0;
  22. 		while(!q.empty()){
  23. 			string ss = q.front().first;
  24. 			int pp = q.front().second;
  25. 			int dist = vis[ss];
  26. 			q.pop();
  27. 			if(pp>0){
  28. 				swap(ss[pp],ss[pp-1]);
  29. 				if(!vis.count(ss)){
  30. 					if(ss==f){
  31. 						cout<<dist+1<<"\n";
  32. 						break;
  33. 					}
  34. 					vis[ss]=dist+1;
  35. 					q.push({ss,pp-1});
  36. 				}
  37. 				swap(ss[pp],ss[pp-1]);
  38. 			}
  39. 			if(pp<n-1){
  40. 				swap(ss[pp],ss[pp+1]);
  41. 				if(!vis.count(ss)){
  42. 					if(ss==f){
  43. 						cout<<dist+1<<"\n";
  44. 						break;
  45. 					}
  46. 					vis[ss]=dist+1;
  47. 					q.push({ss,pp+1});
  48. 				}
  49. 				swap(ss[pp],ss[pp+1]);
  50. 			}
  51. 			if(pp>1 && ss[pp-1]!=ss[pp-2]){
  52. 				swap(ss[pp],ss[pp-2]);
  53. 				if(!vis.count(ss)){
  54. 					if(ss==f){
  55. 						cout<<dist+1<<"\n";
  56. 						break;
  57. 					}
  58. 					vis[ss]=dist+1;
  59. 					q.push({ss,pp-2});
  60. 				}
  61. 				swap(ss[pp],ss[pp-2]);
  62. 			}
  63. 			if(pp<n-2 && ss[pp+1]!=ss[pp+2]){
  64. 				swap(ss[pp],ss[pp+2]);
  65. 				if(!vis.count(ss)){
  66. 					if(ss==f){
  67. 						cout<<dist+1<<"\n";
  68. 						break;
  69. 					}
  70. 					vis[ss]=dist+1;
  71. 					q.push({ss,pp+2});
  72. 				}
  73. 				swap(ss[pp],ss[pp+2]);
  74. 			}
  75. 		}
  76. 	}
  77. 	return 0;
  78. }
Success #stdin #stdout 0s 3472KB
comments (?)
stdin
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2
a_b
ab_
aba_a
_baaa
stdout
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1
2
https://ideone.com/rMnS6j
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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