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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. class Main
  8. {
  9. 	public static void main (String[] args) throws java.lang.Exception
  10. 	{
  11. 		int n = 6;
  12. 		int[] nums = {2, 1, -4, 9, 2, -1};
  13.  
  14. 		System.out.println("Maximum sum of two non-overlapping subarrays: " + maxTwoNonOverlappingSubarraysSum(nums));
  15. 	}
  16.  
  17. 	public static int maxTwoNonOverlappingSubarraysSum(int[] arr){
  18. 		int n = arr.length;
  19. 		int[] prefixMaxSum = calculatePrefixMaxSum(arr);
  20. 		int[] suffixMaxSum = calculateSuffixMaxSum(arr);
  21. 		int max = 0;
  22. 		for(int i = 0 ; i < n - 1 ; i++){
  23. 			max = Math.max(max , prefixMaxSum[i] + suffixMaxSum[i + 1]);
  24. 		}
  25. 		return max;
  26. 	}
  27.  
  28. 	public static int[] calculatePrefixMaxSum(int[] arr){
  29. 		int n = arr.length;
  30. 		int[] ans = new int[n];
  31. 		int curMax = 0 , max = 0;
  32. 		for(int i = 0 ; i < n ; i++){
  33. 			curMax = Math.max(arr[i] + curMax , Math.max(arr[i] , 0));
  34. 			max = Math.max(max , curMax);
  35. 			ans[i] = max;
  36. 		}
  37. 		return ans;
  38. 	}
  39.  
  40. 	public static int[] calculateSuffixMaxSum(int[] arr){
  41. 		int n = arr.length;
  42. 		int[] ans = new int[n];
  43. 		int curMax = 0 , max = 0;
  44. 		for(int i = n - 1 ; i >= 0 ; i--){
  45. 			curMax = Math.max(arr[i] + curMax , Math.max(arr[i] , 0));
  46. 			max = Math.max(max , curMax);
  47. 			ans[i] = max;
  48. 		}
  49. 		return ans;
  50. 	}
  51. }
  52.  
Success #stdin #stdout 0.11s 55600KB
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Standard input is empty
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Maximum sum of two non-overlapping subarrays: 14
https://ideone.com/ELJ7jA
language:
Java (HotSpot 12)
created:
14 days ago
visibility:
public

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