Find pairs of numbers in an array with a given sum

Pairs.groovy

def findPairs1(nums, limit) {
   print "$nums, $limit => "
   def pairs = []

   nums.eachWithIndex { n1, i1 ->
      nums.eachWithIndex { n2, i2 ->
         if (i1 != i2 && (n1 + n2) == limit) {
            pairs << [ n1, n2 ].sort()
         }
      }
   }

   pairs.unique()
}

def findPairs2(nums, limit) {
   print "$nums, $limit => "
   def mem = [:]

   nums.collect { n ->
      def diff = limit - n

      if (!mem[diff]) {
         mem[n] = 1
         []
      } else {
         [ n, diff ]
      }
   }.findAll()
}

println findPairs1([ 1, 98, 99, 2, 5 ], 100)
println findPairs1([ 50, 50 ], 100)
println findPairs1([ 5, 3, 7, 9, 6, 1 ], 10)

println findPairs2([ 1, 98, 99, 2, 5 ], 100)
println findPairs2([ 50, 50 ], 100)
println findPairs2([ 5, 3, 7, 9, 6, 1 ], 10)