map

//作业
var list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; 
var selectedList = [1, 5]; 
var ret = [];
var hash = {};
function union( list, selectedList ){
    var ret = [];
    list.forEach(function(item){
        hash[item] = false;
    });
    selectedList.forEach(function(item){
        hash[ item ] = true;
    })
    for(var key in hash){
        if( !hash[key] ){
            ret.push(key);
        }
    }
    return ret;
} 

function selectorAll( list, selectedList ){
    var ret = [];
    list.forEach( function( item ){
        hash[itme] = false;
    });
    selectedList.forEach(function( item ){
        hash[ item ] = true;
    })
    for(var key in hash){
        if( hash[key] ){
            ret.push(key);
        }
    }
    for(var key in hash){
        if( !hash[key] ){
            ret.push(key);
        }
    }
    return ret;
}