Add binomialCoefficient

test/binomialCoefficient/binomialCoefficient.js

@@ -0,0 +1,11 @@
+const binomialCoefficient = (n, k) => {
+if (Number.isNaN(n) || Number.isNaN(k)) return NaN;
+if (k < 0 || k > n) return 0;
+if (k === 0 || k === n) return 1;
+if (k === 1 || k === n - 1) return n;
+if (n - k < k) k = n - k;
+let res = n;
+for (let j = 2; j <= k; j++) res *= (n - j + 1) / j;
+return Math.round(res);
+};
+module.exports = binomialCoefficient;