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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. 		Scanner in = new Scanner(System.in);
  14. 		int n = in.nextInt();
  15.  
  16. 		int b[] = new int[n+1];
  17.  
  18. 	    for (int i = 1; i <= n; i++) {
  19.             b[i] = in.nextInt();
  20.         }
  21.  
  22. 		int prefix[] = new int[n+1];//1-base indexing 
  23. 		int suffix[] = new int[n+1];
  24.  
  25. 		prefix[1] = 1;
  26.  
  27. 		for(int i =2;i<=n;i++){
  28. 			if(b[i-1] >b[i]){
  29. 				prefix[i] = prefix[i-1] +1;
  30. 			}
  31. 			else{
  32. 				prefix[i] = 1;
  33. 			}
  34. 		}
  35.  
  36. 		suffix[n] = 1;
  37. 		for(int j=n-1;j>=1;j--){
  38. 			if(b[j]<b[j+1]){
  39. 				suffix[j] = suffix[j+1] +1;
  40. 			}
  41. 			else{
  42. 				suffix[j] = 1;
  43. 			}
  44. 		}
  45.  
  46. 		long valleys = 0;
  47. 		for(int i =2;i<n;i++){
  48. 			if(b[i-1] >b[i] && b[i+1]>b[i]){
  49. 				int leftPart = prefix[i-1];
  50. 				int rightPart = suffix[i+1];
  51. 				valleys += (long)(leftPart*rightPart);
  52. 			}
  53. 		}
  54. 	System.out.println(valleys);
  55.  
  56. 	}
  57. }
Success #stdin #stdout 0.17s 56600KB
comments (?)
stdin 
6
5 4 3 2 11 12
stdout 
6
https://ideone.com/y07vg5
language:
Java (HotSpot 12)
created:
17 days ago
visibility:
public

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