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var ProductOfNumbers = function () {
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  this.products = [];
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};
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ProductOfNumbers.prototype.add = function (num) {
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  if (num == 0) {
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    this.products = [];
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  } else {
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    const N = this.products.length;
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    this.products.push(N == 0 ? num : num * this.products[N - 1]);
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  }
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};
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ProductOfNumbers.prototype.getProduct = function (k) {
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  const N = this.products.length;
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  if (N - k < 0) return 0;
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  if (N == k) return this.products[N - 1];
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  return this.products[N - 1] / this.products[N - k - 1];
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};