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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 n = 4;
  14. 		int k = 4;
  15. 		int[] arr = new int[]{1,3,2,4};
  16.  
  17. 		System.out.println(helper(arr,n,k));
  18.  	}
  19.  	static int helper(int[]arr, int n, int k){
  20.  		int[] preSum = new int[n];
  21.  		HashMap<Integer,Integer> map = new HashMap<>();
  22.  		int cnt = 0;
  23.  		preSum[0] = arr[0];
  24.  		for(int i=1;i<n;i++){
  25.  			preSum[i] = preSum[i-1]+arr[i];
  26.  		}
  27.  		map.put(0,1);
  28.  		for(int i=0;i<n;i++){
  29.  			int modFreq = (preSum[i]%k-i%k+k)%k;
  30.  			cnt+= map.getOrDefault(modFreq,0);
  31.  			map.put(modFreq,map.getOrDefault(modFreq,0)+1);
  32.  		}
  33.  
  34.  		return cnt;
  35.  	}
  36. }
Success #stdin #stdout 0.07s 54564KB
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https://ideone.com/8ckhXl
language:
Java (HotSpot 12)
created:
1 day ago
visibility:
public

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