ARRAY TRANSFORMATION

• Problem Description

  
  "Given n numbers, you can perform the following operation any number of times : Choose any subset of the numbers (possibly empty), none of which are 0. Decrement the numbers in the subset by 1, and increment the numbers not in the subset by K.
  
  Is it possible to perform operations such that exactly n - 1 numbers become 0 ?

• CODING ARENA

• #include <stdio.h>

  int main()

  {

    int t,n,k,a[100],hash[1000],i,ans,x;

    scanf("%d",&t);

    while(t--)

    {

      scanf("%d %d",&n,&k);

      for(i=0;i<1000;i++)hash[i]=0;

      ans=0;

      for(i=0;i<n;i++)

      {

        scanf("%d",&a[i]);

        x=(a[i]%(k+1));

        hash[x]++;

        if(hash[x]>n-2)ans=1;

      }

      if(ans)

        printf("YES\n");

      else

        printf("NO\n");

    }

    return 0;

  }

  
  

• Test Case 1

  
  Input (stdin)

  3
  
  2 1
  
  10 10
  
  3 2
  
  1 2 2
  
  3 2
  
  1 2 3
  
  

  Expected Output

  YES
  
  YES
  
  NO

• Test Case 2

  
  Input (stdin)

  3
  
  2 1 4
  
  3 2 4
  
  1 2 2
  
  3 2 3
  
  1 2 4 4
  
  

  Expected Output

  YES
  
  YES
  
  YES