Merge pull request #5 from pro-js/basicMath

Math - 2

Author: zubayerhimel

lib/isMethod.js

@@ -43,13 +43,42 @@ export function isPrime(num) {
  * palindromeNumber(45674); // false
  * palindromeNumber(4567654); // true
  */
-export function isPalindrome(number) {
-  var final = 0,
-    temp = number;
-  while (number > 0) {
-    var rem = number % 10;
-    number = parseInt(number / 10);
-    final = final * 10 + rem;
-  }
-  return final == temp;
+
+exports.isPalindrome = (number) => {
+  var final = 0, temp = number;
+  while(number>0) { var rem = number % 10; number = parseInt(number / 10);
+      final = (final * 10) + rem; } return final == temp;
+}
+
+/**
+ * Check positive number
+ * @param {*} number
+ * isPositive(45674); // true
+ * isPositive(-4567654); // false
+ */
+exports.isPositive = (number) => {
+  if (number === 0) return false;
+  return ((number >> 31) & 1) === 0;
 }
+
+/**
+ * Check negative number
+ * @param {*} number
+ * isNegative(45674); // false
+ * isNegative(-4567654); // true
+ */
+exports.isNegative = (number) => {
+  if (number === 0) return false;
+  return ((number >> 31) & 1) === 1;
+}
+
+/**
+ * Check isPowerOfTwo number
+ * @param {*} number
+ * isPowerOfTwo(35); // false
+ * isPowerOfTwo(32); // true
+ */
+exports.isPowerOfTwo = (number) => {
+  if (number < 1) return false;
+  return (number & (number - 1)) === 0;
+}

lib/number.js

@@ -46,3 +46,96 @@ export function toFixed(number, fixed) {
 export function getFactorial(number) {
   return number != 1 ? number * getFactorial(number - 1) : 1;
 }
+
+let factorialCalculate = (number) => {
+  return number > 1 ? number * factorialCalculate(number - 1) : 1;
+};
+
+/**
+ * Pass a base number, power number and calculate the power of the number
+ * @param {*} number
+ */
+exports.bigPower = (base, power) => {
+  if (power === 0) return 1;
+  if (power % 2 === 0) {
+    const multiplier = bigPower(base, power / 2);
+    return multiplier * multiplier;
+  }
+  const multiplier = bigPower(base, Math.floor(power / 2));
+  return multiplier * multiplier * base;
+}
+
+/**
+ * Return a fibonacci sequence as an array.
+ * @param number
+ * @return {number[]}
+ * console.log(fibSequence(10)) // [ 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 ]
+ */
+exports.fibSequence = (number) => {
+  let fibSeq = [1], currentValue = 1, previousValue = 0;
+  if (number === 1) return fibSeq;
+  let iterationsCounter = number - 1;
+  while (iterationsCounter) {
+    currentValue += previousValue;
+    previousValue = currentValue - previousValue;
+    fibSeq.push(currentValue);
+    iterationsCounter -= 1;
+  }
+  return fibSeq;
+}
+
+/**
+ * Calculate fibonacci number at specific position using Dynamic Programming approach.
+ * @param number
+ * @return {number}
+ * console.log(fibonacciNth(10)) // 55
+ */
+exports.fibNth = (number) => {
+  let currentValue = 1, previousValue = 0;
+  if (number === 1) return 1;
+  let iterationsCounter = number - 1;
+  while (iterationsCounter) {
+    currentValue += previousValue;
+    previousValue = currentValue - previousValue;
+    iterationsCounter -= 1;
+  }
+  return currentValue;
+}
+
+/**
+ * Get pascal Triangle
+ * @param {number} lineNumber - zero based.
+ * @return {number[]}
+ * console.log(pascalTriangle(10)) 
+ * [ 1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1 ]
+ */
+exports.pascalTriangle = (lineNumber) => {
+  let currentLine = [1], currentLineSize = lineNumber + 1;
+  for (let numIndex = 1; numIndex < currentLineSize; numIndex += 1) {
+    currentLine[numIndex] = currentLine[numIndex - 1] * (lineNumber - numIndex + 1) / numIndex;
+  }
+  return currentLine;
+}
+
+/**
+ * Get prime list
+ * @param {number}
+ * @return {primes[]}
+ * console.log(getPrimeList(20)) // [ 2, 3, 5, 7, 11, 13, 17, 19 ]
+ */
+exports.getPrimeList = (number) => {
+  let isPrime = new Array(number + 1).fill(true), primes = [];
+  isPrime[0] = false;
+  isPrime[1] = false;
+  for (let num = 2; num <= number; num += 1) {
+    if (isPrime[num] === true) {
+      primes.push(num);    
+      let nextnum = num * num;
+      while (nextnum <= number) {
+        isPrime[nextnum] = false;
+        nextnum += num;
+      }
+    }
+  }
+  return primes;
+}