借助set

注意:count = map.get(numbers[i]) || 0;

function MoreThanHalfNum_Solution(numbers)
{
  let map = new Map();
  let count;
  for(let i=0; i<numbers.length; i++){
    count = map.get(numbers[i]) || 0;
    map.set(numbers[i],count+1);
  }
  for(let i=0; i<numbers.length; i++)
    if(map.get(numbers[i]) > numbers.length/2)
      return numbers[i];
}
module.exports = {
    MoreThanHalfNum_Solution : MoreThanHalfNum_Solution
};