Underdoge

function alternatingSums(a) {
    var sum = a.reduce(function(acc, val,currentIndex) {
        if(currentIndex%2==0)
            acc[0] += val;
        else
            acc[1] += val;
        return acc;
    }, [0,0]);
    return sum;
}

Underdoge

function flip(flipped){
    if(flipped.indexOf('(')>=0){
        var j=0;
        var a=0;
        var b=0;
        var reversed=[];
        while (j<flipped.length&&b==0) {
            if(flipped[j]=='('){
                 a=j;
            }

Underdoge

function sortByHeight(a) {
    var b=a.slice(0);
    var x=0;
    for (var i=0;i<b.length;i++){
        if(b[i]<0){
            b.splice(i,1);
        }
    }
    b.sort((a,b)=>a-b);
    for (var j=0;j<a.length;j++){

Underdoge

function isLucky(n) {
    var numbers=n.toString().split("");
    var a=0,b=0;
    for(i=0;i<numbers.length/2;i++){
        a+=parseInt(numbers[i],10);
        b+=parseInt(numbers[numbers.length/2+i],10);
    }
    return a===b;
}

Underdoge

function commonCharacterCount(s1, s2) {
    var string1=s1.split('');
    var string2=s2.split('');
    var common=0;
    
    for(var i=0;i<string1.length;i++){
        if(string2.indexOf(string1[i])>=0){
            common++;
            string2.splice(string2.indexOf(string1[i]),1);
        }

Underdoge

function allLongestStrings(inputArray) {
    var result=[""];
    var count=0;
    for(var i=0;i<inputArray.length;i++){
        if(inputArray[i].length>=result[result.length-1].length){
            if(inputArray[i].length>result[result.length-1].length)
                count=1;
            else
                count++
            result.push(inputArray[i]);            

Underdoge

function matrixElementsSum(matrix) {
    price=0;
    for(var y=0;y<matrix.length;y++)
        for(var x=0;x<matrix[0].length;x++){
            if(y==0)
                price+=matrix[y][x];
            else{
                if(matrix[y-1][x]==0)
                    matrix[y][x]=0;
                price+=matrix[y][x];

Underdoge

function almostIncreasingSequence(sequence){
    var errors=0;
    for(var i=0;i+1<sequence.length&&errors<2;i++)
        if(sequence[i]>=sequence[i+1]){
            errors++;
            if(i+2<sequence.length&&i>0)
                if(sequence[i]>=sequence[i+2])
                    errors++;
        }
    return errors<=1;

Underdoge

function isSmooth(arr) {
    return (arr.length%2==0) ? arr[0]===arr[arr.length-1]&&arr[0]===(arr[arr.length/2-1]+arr[arr.length/2]):arr[0]==arr[arr.length-1]&&arr[0]==(arr[Math.floor(arr.length/2)]);
}

Underdoge

function makeArrayConsecutive2(statues) {
   statues=statues.sort((a,b)=>a-b);
   return(statues[statues.length-1]-statues[0]+1-statues.length);
}