function moveZeros(arr) {
let k = 0;
for(let i = 0; i < arr.length; i++) {
if(arr[i]) {
arr[k++] = arr[i]
}
}
for(; k < arr.length; k ++) {
arr[k] = 0;
}
}
function moveZeros2(arr) {
let k = 0;
for(let i = 0; i < arr.length; i++) {
if(arr[i]) {
if(k===i) {
k++
}else{
swap(arr,k, i)
k++
}
}
}
}
function swap(arr, a, b){
const temp = arr[a];
arr[a] = arr[b];
arr[b] = temp
}
const arr = [1,3,0,0,34,3,0,2,345]
moveZeros2(arr)
console.log(arr)