Least Number of Unique Integers after K Removals LeetCode solution in JavaScript

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var findLeastNumOfUniqueInts = function (arr, k) {
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  var hsh = {};
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  var instance = {}; // store set with index # of occurence
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  var count = 0;
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  for (var i = 0; i < arr.length; i++) {
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    if (hsh[arr[i]] == null) {
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      count++;
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      hsh[arr[i]] = 1;
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      if (instance[1] == null) {
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        var intro = new Set();
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        intro.add(arr[i]);
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        instance[1] = intro;
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      } else {
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        instance[1].add(arr[i]);
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      }
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    } else {
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      hsh[arr[i]]++;
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      var numTimes = hsh[arr[i]];
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      instance[numTimes - 1].delete(arr[i]);
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      if (instance[numTimes] == null) {
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        instance[numTimes] = new Set();
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        instance[numTimes].add(arr[i]);
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      } else {
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        instance[numTimes].add(arr[i]);
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      }
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    }
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  }
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  var removenum = 0;
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  for (key in instance) {
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    var instanceKey = instance[key].size;
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    if (k == 0) {
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      break;
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    } else if (k >= key * instanceKey) {
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      k -= key * instanceKey;
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      count -= instanceKey;
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    } else {
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      count -= Math.floor(k / key);
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      break;
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    }
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  }
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  return count;
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};