38. Count and Say

https://leetcode.com/problems/count-and-say/

Count and Say - LeetCode

/**
 * @param {number} n
 * @return {string}
 */
const hash = {};
hash[0] = '';
hash[1] = '1';
hash[2] = '11';
hash[3] = '21';
hash[4] = '1211';
hash[5] = '111221';

const  say = function(p_num)
{   
    const l_number = p_num.toString();
    var res = "";
        

    var cnt     = 1;
    var before  = l_number.charAt(0);
    var elem    = '';

    
    for( var i=1; i<l_number.length; ++i )
    {
        elem = l_number.charAt(i);
        if( elem == before )
            ++cnt;
        else
        {
            res += cnt + '' + before;
            before  = elem;
            cnt     = 1;
        }
    }

    res += cnt.toString() + before.toString();
    return res;
}

var countAndSay = function(n) {    
    const find = function(p_num)
    {
        return hash[p_num] ? hash[p_num]:( hash[p_num] = say( find(Number(p_num)-1) ) );        
    }    
    
    return find(n);
};