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  1. #include <iostream>
  2. #include <map>
  3. using namespace std;
  4.  
  5. struct node
  6. {
  7. 	int x,y;
  8. 	node(int x1,int y1)
  9. 	{
  10. 		x=x1;
  11. 		y=y1;
  12. 	}
  13. };
  14.  
  15. int main() {
  16.  
  17. 	int n,m;
  18. 	cin>>n>>m;
  19.  
  20. 	int a[n];
  21. 	int indices[n+1];
  22. 	for(int i=0;i<n;i++)
  23. 	{
  24. 		cin>>a[i];
  25. 		indices[a[i]]=i;
  26. 	}
  27.  
  28. 	int ans=1;
  29. 	for(int j=1;j<n;j++)
  30. 	{
  31. 		if(indices[j] > indices[j+1])
  32. 		{
  33. 			ans++;
  34. 		}
  35. 	}
  36. 	//cout<<"ans="<<ans<<endl;	
  37.  
  38. 	for(int i=0;i<m;i++)
  39. 	{
  40. 		int x,y;
  41. 		cin>>x>>y;
  42.  
  43. 		x--;
  44. 		y--;
  45.  
  46. 		map<int,map<int,int> > updatedPairs;
  47. 		if(a[x]+1 <=n)
  48. 		{
  49. 			updatedPairs[a[x]][a[x]+1]=1;
  50. 		}
  51. 		if(a[x]-1 >=0)
  52. 		{
  53. 			updatedPairs[a[x]-1][a[x]]=1;
  54. 		}
  55. 		if(a[y]+1 <=n)
  56. 		{
  57. 			updatedPairs[a[y]][a[y]+1]=1;
  58. 		}
  59. 		if(a[y]-1 >=0)
  60. 		{
  61. 			updatedPairs[a[y]-1][a[y]]=1;
  62. 		}
  63.  
  64.  
  65. 		for(auto it=updatedPairs.begin();it!=updatedPairs.end();it++)
  66. 		{
  67. 			map<int,int> Map = it->second;
  68. 			for(auto it2=Map.begin();it2!=Map.end();it2++)
  69. 			{
  70. 				ans-=(indices[it->first] > indices[it2->first]);
  71. 			}
  72. 		}
  73.  
  74. 		//cout<<"ans="<<ans<<endl;
  75.  
  76. 		int temp = a[x];
  77. 		a[x] = a[y];
  78. 		a[y] = temp;
  79.  
  80. 		indices[a[x]]=x;
  81. 		indices[a[y]]=y;
  82.  
  83. 		for(auto it=updatedPairs.begin();it!=updatedPairs.end();it++)
  84. 		{
  85. 			map<int,int> Map = it->second;
  86. 			for(auto it2=Map.begin();it2!=Map.end();it2++)
  87. 			{
  88. 				ans+=(indices[it->first] > indices[it2->first]);
  89. 			}
  90. 		}
  91.  
  92. 		cout<<ans<<endl;
  93. 	}
  94.  
  95.  
  96.  
  97. 	return 0;
  98. }
Success #stdin #stdout 0.01s 5288KB
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https://ideone.com/EQkSbY
language:
C++14 (gcc 8.3)
created:
11 days ago
visibility:
public

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