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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. vector<int>getprefixMax(vector<int>&arr){
  4. 	int n=arr.size();
  5. 	vector<int>newprefixSum(n+1,0);
  6. 	int curr=arr[1];
  7. 	newprefixSum[1]=arr[1];
  8. 	for(int i=2;i<=n;i++){
  9. 		curr=max({0,curr+arr[i],arr[i]});
  10. 		newprefixSum[i]=curr;
  11. 	}
  12. 	return newprefixSum;
  13.  
  14. }
  15. vector<int>getsuffixMax(vector<int>&arr){
  16. 	int n=arr.size();
  17. 	vector<int>newsuffixSum(n+1,0);
  18. 	int curr=arr[n];
  19. 	newsuffixSum[n]=arr[n];
  20. 	for(int i=n-1;i>0;i--){
  21. 		curr=max({0,curr+arr[i],arr[i]});
  22. 		newsuffixSum[i]=curr;
  23. 	}
  24. 	return newsuffixSum;
  25.  
  26. }
  27.  
  28. int getMaxSum(vector<int>&arr){
  29. 	int n=arr.size();
  30. 	vector<int>prefixMax=getprefixMax(arr);
  31. 	vector<int>suffixMax=getsuffixMax(arr);
  32.  
  33. 	vector<int>finalprefixMax(n+2,0);
  34. 	vector<int>finalsuffixMax(n+2,0);
  35.  
  36. 	finalprefixMax[1]=prefixMax[1];
  37. 	for(int i=2;i<=n;i++){
  38. 		finalprefixMax[i]=max(finalprefixMax[i-1],prefixMax[i]);
  39. 	}
  40.  
  41. 	finalsuffixMax[n]=prefixMax[n];
  42. 	for(int i=n-1;i>0;i--){
  43. 		finalsuffixMax[i]=max(finalsuffixMax[i+1],suffixMax[i]);
  44. 	}
  45. 	int finalMax=0;
  46. 	for(int i=0;i<=n;i++){
  47. 		finalMax=max({finalMax,finalprefixMax[i]+finalsuffixMax[i+1]});
  48. 	}
  49. 	return finalMax;
  50.  
  51. }
  52.  
  53. int main() {
  54. 	// your code goes here
  55. 	int n;
  56. 	cin>>n;
  57. 	vector<int>arr(n+1);
  58. 	for(int i=1;i<=n;i++){
  59. 		cin>>arr[i];
  60. 	}
  61. 	cout<<"The maximum sum of non-overlapping subarrays is:"<<getMaxSum(arr);
  62.  
  63.  
  64. 	return 0;
  65. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin 
7
1 5 -3 4 -9 9 2
stdout 
The maximum sum of non-overlapping subarrays is:22
https://ideone.com/DXrrNT
language:
C++ (gcc 8.3)
created:
2 days ago
visibility:
public

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