static void findSumPairs ( int a [ ] , int n ) {
  Map < Integer , Integer > mpp = new HashMap < > ( ) ;
  for ( int i = 0 ;
  i < n - 1 ;
  i ++ ) {
    for ( int j = i + 1 ;
    j < n ;
    j ++ ) {
      mpp . put ( a [ i ] + a [ j ] , mpp . get ( a [ i ] + a [ j ] ) == null ? 1 : mpp . get ( a [ i ] + a [ j ] ) + 1 ) ;
    }
  }
  int occur = 0 ;
  for ( Map . Entry < Integer , Integer > entry : mpp . entrySet ( ) ) {
    if ( entry . getValue ( ) > occur ) {
      occur = entry . getValue ( ) ;
    }
  }
  for ( Map . Entry < Integer , Integer > entry : mpp . entrySet ( ) ) {
    if ( entry . getValue ( ) == occur ) System . out . println ( entry . getKey ( ) ) ;
  }
}

static void findSumPairs ( int a [ ] , int n ) { Map < Integer , Integer > mpp = new HashMap < > ( ) ; for ( int i = 0 ; i < n - 1 ; i ++ ) { for ( int j = i + 1 ; j < n ; j ++ ) { mpp . put ( a [ i ] + a [ j ] , mpp . get ( a [ i ] + a [ j ] ) == null ? 1 : mpp . get ( a [ i ] + a [ j ] ) + 1 ) ; } } int occur = 0 ; for ( Map . Entry < Integer , Integer > entry : mpp . entrySet ( ) ) { if ( entry . getValue ( ) > occur ) { occur = entry . getValue ( ) ; } } for ( Map . Entry < Integer , Integer > entry : mpp . entrySet ( ) ) { if ( entry . getValue ( ) == occur ) System . out . println ( entry . getKey ( ) ) ; } }
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