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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static void main (String[] args) throws java.lang.Exception
  11. 	{
  12. 		// your code goes here
  13. 		int[] A = {1, 2, 3, 2, 1};
  14. 		int n = 5;
  15.  
  16. 		int[]dp1 = new int[n + 1];
  17. 		int[]dp2 = new int[n + 1];
  18. 		int[]DP1 = new int[n + 1];
  19. 		int[]DP2 = new int[n + 1];
  20.  
  21. 		for(int i = 0; i < n; i++){
  22. 			dp1[i] = 1;
  23.  
  24. 			for(int j = 1; j < A[i]; j++){
  25. 				dp1[i] += DP1[j];
  26. 			}
  27. 			DP1[A[i]] += dp1[i]; 
  28. 		}
  29.  
  30. 		for(int i = n - 1; i >= 1 ; i--){
  31. 			dp2[i] = 1;
  32.  
  33. 			for(int j = 1; j < A[i]; j++){
  34. 				dp2[i] += DP2[j];
  35. 			}
  36. 			DP2[A[i]] += dp2[i]; 
  37. 		}
  38.  
  39. 		int ans = 0;
  40.  
  41. 		for(int i = 0; i < n; i++){
  42. 			ans += (dp1[i] - 1) * (dp2[i] - 1);
  43. 		}
  44. 		System.out.println(ans);
  45. 	}
  46. }
Success #stdin #stdout 0.07s 54592KB
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11
https://ideone.com/KeKnhC
language:
Java (HotSpot 12)
created:
15 hours ago
visibility:
public

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