Answer 1

function find(str){
let Obj={};
	str.split('').reduce((o,p,index)=>{
		o===p?(Obj[o]?Obj[o]=Obj[o]++:Obj[o]=2):null
		return p
	});
	Object.keys(Obj).forEach(k=>{
		if(Obj[k]!==Math.max(...Object.values(Obj))){
			delete Obj[k]
		}
	});
	return Obj;
}