DSA

const fish = ['dory', 'bruce', 'marlin', 'nemo'];
const nemo = ['nemo'];
const everyone = ['dory', 'bruce', 'marlin', 'nemo', 'gill', 'bloat', 'nigel', 'squirt', 'darla', 'hank'];
const large = new Array(10).fill('nemo');

function findNemo2(fish) {
  let t0 = performance.now();
  for (let i = 0; i < fish.length; i++) {
    if (fish[i] === 'nemo') {
      console.log('Found NEMO!');
    }
  }
  let t1 = performance.now();
  console.log("Call to find Nemo took " + (t1 - t0) + " milliseconds.");
}

findNemo2(everyone)

// What is the Big O of the below function? (Hint, you may want to go line by line)
function funChallenge(input) {
  let a = 10;   // O(1)
  a = 50 + 3;   // O(1)

  for (let i = 0; i < input.length; i++) {  // O(n)
    anotherFunction();  // O(n)
    let stranger = true;    // O(n)
    a++;    // O(n)
  }
  return a; // O(1)
}

// Big O calculation - 3 + n + n + n + n = 3 + 4n -> O(3 + 4n) -> O(n)

class MyArray {

    constructor() {
        this.length = 0;
        this.data = {};
    }

    get(index) {
        return this.data[index];
    }

    push(item) {
        this.data[this.length] = item;
        this.length++;

        return this.length;
    }

    pop() {
        const lastItem = this.data[this.length - 1];

        delete this.data[this.length - 1];
        this.length--;

        return lastItem;
    }

    delete(index) {
        const item = this.data[index];

        this.shiftItems(index);

        return item;
    }

    shiftItems(index) {
        for (let i = index; i < this.length - 1; i++) {
            this.data[i] = this.data[i + 1];
        }

        delete this.data[this.length - 1];
        this.length--;
    }
}

class HashTable {
  constructor(size){
    this.data = new Array(size);
  }

  _hash(key) {
    let hash = 0;
    for (let i =0; i < key.length; i++){
        hash = (hash + key.charCodeAt(i) * i) % this.data.length
    }
    return hash;
  }
  
  set(key, value) {
      let address = this._hash(key)
      if (!this.data[address]) {
          this.data[address] = []
      }
      this.data[address].push([key, value])
      //console.log(this.data)
  }
  
  get(key) {
      const address = this._hash(key)
      const currentBucket = this.data[address]
      console.log(currentBucket)
      if (currentBucket) {
          for (let i=0; i < currentBucket.length; i++) {
              if (currentBucket[i][0] === key) {
                  console.log(currentBucket[i])
                  return currentBucket[i][1]
              }
          }
      }
      return undefined
  }
  
  keys() {
      let result = []
      console.log(this.data)
      
      for (let i=0; i < this.data.length; i++) {
          if (this.data[i]) {
              if (this.data[i].length > 1) {
                for (let j=0; j < this.data[i].length; j++) {
                  result.push(this.data[i][j][0])
                }
              } else {
                result.push(this.data[i][0][0])
              }
          }
      }
      console.log(result)
      return result
  }
}

const myHashTable = new HashTable(5);
myHashTable.set('grapes', 10000)
myHashTable.set('apples', 9)
myHashTable.set('oranges', 4)
myHashTable.set('kiwis', 2)
//console.log(myHashTable.get('grapes'))
myHashTable.keys()

//myHashTable.get('apples')