10 posts tagged with "math"

/**
 * @param {number} n
 * @return {string[]}
 */
var fizzBuzz = function (n) {
  const result = [];

  for (let i = 1; i <= n; i++) {
    if (i % 15 === 0) {
      result.push('FizzBuzz');
    } else if (i % 5 === 0) {
      result.push('Buzz');
    } else if (i % 3 === 0) {
      result.push('Fizz');
    } else {
      result.push(i.toString());
    }
  }

  return result;
};

/**
 * @param {string} s
 * @return {number}
 */
var romanToInt = function (s) {
  let total = 0;

  for (let i = 0; i < s.length; i++) {
    if (values[s[i]] < values[s[i + 1]]) {
      total += values[s[i + 1]] - values[s[i]];
      i++;
    } else {
      total += values[s[i]];
    }
  }
  return total;
};

const values = {
  I: 1,
  V: 5,
  X: 10,
  L: 50,
  C: 100,
  D: 500,
  M: 1000,
};

/**
 * @param {number} columnNumber
 * @return {string}
 */
var convertToTitle = function (columnNumber) {
  // String.fromCharCode(65) === "A"
  // 한 자릿수일 경우
  if (columnNumber - 1 < 26) {
    return String.fromCharCode(65 + ((columnNumber - 1) % 26));
  }

  // 두 자릿수 이상일 경우
  let result = '';
  while (columnNumber > 0) {
    const remainder = (columnNumber - 1) % 26;
    const remainderCharCode = String.fromCharCode(65 + remainder);
    result = remainderCharCode + result;
    columnNumber = parseInt((columnNumber - 1) / 26);
  }
  return result;
};

/**
 * @param {string} columnTitle
 * @return {number}
 */
var titleToNumber = function (columnTitle) {
  if (columnTitle.length === 1) {
    return (columnTitle.charCodeAt(0) % 65) + 1;
  }

  let result = 0;

  for (let i = columnTitle.length - 1; i >= 0; i--) {
    const strCode = (columnTitle[i].charCodeAt(0) % 65) + 1;
    if (i === columnTitle.length - 1) {
      result += strCode;
    } else {
      result += strCode * 26 ** (columnTitle.length - i - 1);
    }
  }
  return result;
};

/**
 * @param {number} n
 * @return {boolean}
 */
var isHappy = function (n) {
  let set = new Set();

  while (!set.has(n)) {
    set.add(n);
    let s = n.toString();
    n = 0;
    for (let i = 0; i < s.length; ++i) {
      n += squares[s[i]];
    }
    if (n === 1) return true;
  }

  return false;
};

const squares = {
  0: 0,
  1: 1,
  2: 4,
  3: 9,
  4: 16,
  5: 25,
  6: 36,
  7: 49,
  8: 64,
  9: 81,
};

/**
 * @param {number} num
 * @return {number}
 */
var minimumSum = function (num) {
  const numToArr = num.toString().split('');

  for (let i = 1; i < numToArr.length; i++) {
    for (let j = 0; j < i; j++) {
      if (numToArr[i] < numToArr[j]) {
        const smallNum = numToArr[i];
        numToArr[i] = numToArr[j];
        numToArr[j] = smallNum;
      }
    }
  }

  const new1 = numToArr[0] + numToArr[2];
  const new2 = numToArr[1] + numToArr[3];

  return Number(new1) + Number(new2);
};

/**
 * @param {number[]} digits
 * @return {number[]}
 */
var plusOne = function (digits) {
  for (let i = digits.length - 1; i >= 0; i--) {
    digits[i] += 1;

    if (digits[i] === 10) {
      digits[i] = 0;
      if (i === 0) {
        digits.unshift(1);
        return digits;
      }
    } else {
      return digits;
    }
  }
};

/**
 * @param {string} a
 * @param {string} b
 * @return {string}
 */
var addBinary = function (a, b) {
  return (BigInt(`0b${a}`) + BigInt(`0b${b}`)).toString(2);
};

/**
 * @param {number} x
 * @return {number}
 */
var mySqrt = function (x) {
  let result = 0;

  if (x === 0) {
    return 0;
  }

  if (x <= 2) {
    return 1;
  }

  for (let i = 0; i < x; i++) {
    if (i * i > x) {
      result = i - 1;
      break;
    }
  }

  return result;
};

/**
 * @param {number} n
 * @return {number}
 */
var climbStairs = function (n) {
  if (n === 1) {
    return 1;
  }

  const cache = {
    0: 1,
    1: 1,
  };

  for (let i = 2; i <= n; i++) {
    cache[i] = cache[i - 1] + cache[i - 2];
  }

  return cache[n];
};