[문제풀이] Recursion 심화 (2)

// Recursion 사용 x

console.log(capitalizeFirst(["car", "taco", "banana"])); // ['Car','Taco','Banana']

function capitalizeFirst(arr) {
  const newArr = [];
  for (let str of arr) {
    const newStr = str[0].toUpperCase() + str.slice(1, str.length);
    newArr.push(newStr);
  }
  return newArr;
}

// Udemy Solution
function capitalizeFirst (array) {
  if (array.length === 1) {
    return [array[0][0].toUpperCase() + array[0].substr(1)];
  }
  const res = capitalizeFirst(array.slice(0, -1));
  const string = array.slice(array.length - 1)[0][0].toUpperCase() + array.slice(array.length-1)[0].substr(1);
  res.push(string);
  return res;
}

 

function nestedEvenSum(obj) {
  let total = 0;

  function helper(obj) {
    if (typeof obj !== "object") return;
    let arr = Object.keys(obj);
    for (let key of arr) {
      if (obj[key] % 2 === 0) {
        total += obj[key];
      } else {
        helper(obj[key]);
      }
    }
  }
  helper(obj);

  return total;
  // add whatever parameters you deem necessary - good luck!
}


var obj1 = {
  outer: 2,
  obj: {
    inner: 2,
    otherObj: {
      superInner: 2,
      notANumber: true,
      alsoNotANumber: "yup"
    }
  }
}

var obj2 = {
  a: 2,
  b: {b: 2, bb: {b: 3, bb: {b: 2}}},
  c: {c: {c: 2}, cc: 'ball', ccc: 5},
  d: 1,
  e: {e: {e: 2}, ee: 'car'}
};

nestedEvenSum(obj1); // 6
nestedEvenSum(obj2); // 10

// Udemy Solution
function nestedEvenSum (obj, sum=0) {
    for (var key in obj) {
        if (typeof obj[key] === 'object'){
            sum += nestedEvenSum(obj[key]);
        } else if (typeof obj[key] === 'number' && obj[key] % 2 === 0){
            sum += obj[key];
        }
    }
    return sum;
}

 

// Udemy Solution
function capitalizeWords (array) {
  if (array.length === 1) {
    return [array[0].toUpperCase()];
  }
  let res = capitalizeWords(array.slice(0, -1));
  res.push(array.slice(array.length-1)[0].toUpperCase());
  return res;
 
}

// Udemy Solution
function stringifyNumbers(obj) {
  var newObj = {};
  for (var key in obj) {
    if (typeof obj[key] === 'number') {
      newObj[key] = obj[key].toString();
    } else if (typeof obj[key] === 'object' && !Array.isArray(obj[key])) {
      newObj[key] = stringifyNumbers(obj[key]);
    } else {
      newObj[key] = obj[key];
    }
  }
  return newObj;
}

// Udemy Solution - Helper 
function collectStrings(obj) {
    var stringsArr = [];
 
    function gatherStrings(o) {
        for(var key in o) {
            if(typeof o[key] === 'string') {
                stringsArr.push(o[key]);
            }
            else if(typeof o[key] === 'object') {
                return gatherStrings(o[key]);
            }
        }
    }
 
    gatherStrings(obj);
 
    return stringsArr;
}

// Udemy Solution - Helper x
function collectStrings(obj) {
    var stringsArr = [];
    for(var key in obj) {
        if(typeof obj[key] === 'string') {
            stringsArr.push(obj[key]);
        }
        else if(typeof obj[key] === 'object') {
            stringsArr = stringsArr.concat(collectStrings(obj[key]));
        }
    }
 
    return stringsArr;
}