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// Given an input string, and an alphabet, find the shortest substring in the input containing every letter in the alphabet at least once
// “aaccbc”, {‘a’, ‘b’, ‘c’} => “accb"
// "aaaabbbcccdddcdba", [ 'a', 'b', 'c' ] => cdba


for (var i = 0; i < input.length; i++) {
  for (var j = i; j < input.length; j++) {
    var s = input.substring(i,j);
    for (var c : s) {
      if (matcher.contains(c)) {
         
      }
    }
  }
} 

function findShortest(input, matcher){
  
  if(input){
    var result = {};
    
    for(var i=0; i<input.length; i++){
        var matchingSub = input.substring(i,1);
      
        for (var j=0; j<matcher.length; j++){
            
        }
    }
    
  }
    
}
  
// Given an array of integers, find the length of the longest arithmetic subsequence
// arithmetic sequence [0,1,2,...] or [1, -1, -3, -5...] or [1, 1, 1, 1, 1...]
// [1, 3, 8, 5, 10, 10, 10, 7] => 4 
//
// (1, 3 ,5, 7) => 4, (10, 10, 10) => 3
{1 => 3 (2), 8(7), 5(4), 10 (9), 10(9), 7}
{3 => 8 (5) , 
  
function longestSubseq(numbers){
  var subSequenceResult= {};
  for(var i=0; i< numbers.length; i++{
      
      for (var j=i; j<numbers.length; j++){
    
        var diff = numbers[j] > numbers[i] ? numbers[j] - numbers[i] : numbers[i] - numbers[j];
    
        if(subSequenceResult[diff]){
          subSequenceResult[diff].push(numbers[i]); // {2: [1
          subSequenceResult[diff].push(numbers[j]); // {2: [1,3
        }else{
          subSequenceResult[diff] = [numbers[i], numbers[j]];
        }
      }
  }

  var longest = 0;
 Object.keys(subSequenceResult).forEach(function forEach(key){
   longest = Math.max(longest,(subSequenceResult[key] || [] ).length);
 });
 return longest;
  
  

}