andrew.js

const hashmap = (n) => {
  const self = this;
  self.list = [[]];
  self.has = (e) => {
    if (self.list.length >= index + 1) {
      return self.list[index].indexOf(e) >= 0;
    } else {
      return false;
    }
  };
  self.add = (e) => {
    index = e.toString().split('').map(c => c.charCodeAt(0)).reduce((a,b)=>(a+b))%(Math.pow(n, 0.5)|0);
    if (self.list.length >= index + 1) {
      self.list[index].push(e);
    } else {
      while(self.list.length < index + 1) {
        self.list.push([]);
      }
      self.list[index].push(e);
    }
  }
  return self
}
m = hashmap(10000);
for (let i = 0; i < 10000; i++) m.add(i);

start = Date.now()
for (let i = 0; i < 10000; i++) m.has(i);
console.log(Date.now()-start)

console.log(m);

// 1 M elements

// how long does it take to find 1 of 1M elements on average?
// on average 1M checks to find

// what if we have 1000 lists of 1000 items and we know which list its in?
// 1 check to get the list index + 1000 checks worst case