Codingame - Clashes

fastest - Syracuse suite

var n = readline(); // start number
var t = [n];        // final array with all the values, the first one is the start number

while(n !== 1) {
  // if n is even, divide it by 2, else, if it is odd, multiply by 3 and add 1
  n = (n%2 === 0) ? (n/2) : 3*n+1;
  t.push( n );
}

print(t.join(' '))

reverse - codingame ==> cpflrlgtm

// abcd ===> aceg
// codingame ==> cpflrlgtm
Array.prototype.map.call(readline(), (c,i) => String.fromCharCode(c.charCodeAt(0)+i )).join('')

reverse - Palindrome

function checkPalindrom(str) {
    return str == str.split('').reverse().join('');
}

smallest - (UN)HAPPY

// HAPPY / UNHAPPY
function c(s,t){t=(''+s).split('').map(function(o){return o*o}).reduce(function(a,b){return a+b});return (t>9)?c(t):t;}print((c(readline())!=1?'UN':'')+'HAPPY')