Coding

list-max-number-divisible-by-three

// You have L, a list containing some digits (0 to 9). Write a function answer(L) which finds the largest number that can be made from some or all of these digits and is divisible by 3. If it is not possible to make such a number, return 0 as the answer. L will contain anywhere from 1 to 9 digits.  The same digit may appear multiple times in the list, but each element in the list may only be used once.

var a = [3,1,4,1,5,9];
var max = 0;

var pattern = function(arr){
    if(arr.length==1){
        return arr;
    }
    var patterns = [];
    for(var i=0;i<arr.length;i++){
		debugger;
var copyArr = arr.slice(0,arr.length);
copyArr.splice(i,1)
        var sub_patterns = pattern(copyArr);
        for(var j=0;j<sub_patterns.length;j++){
            var num = arr[i]*Math.pow(10,Math.floor(Math.log10(sub_patterns[j]))+1)+sub_patterns[j];
            if(num%3 ==0 && num > max){
				max = num;
            }
            patterns.push(num);
        }
    }
    return patterns;
    
}
pattern(a);