Searching Algorithms with javascript

Searching Algorithms

• 
  

  Linear Search

  it finds what we are searching for by
  brute force, making it easy to implement.
  we will use three different ways in javascript.
  
  first way : search with includes method.
  
  
  *example: Array.includes("something");
  
  *includes method will return True or False.
  
  
  
  second way : search with indexOf method.
  
  
  *example: Array.indexOf("something");
  
  *indexOf method will return number 'the index of the something'
  
  
  third way : search with Find method.
  
  
  *example: Array.find(item => item === "something");
  
  *we write in this method a function and it will return something we search about.
  
  

• 
  

  Binary Search

  Binary search only works on sorted arrays.O(log n) 'big o notation'.
  
  Example : [1,2,3,4,5,6,7,8,9,10] for example if we search for number 7
  
  
  
  we have in this array three things the first thing is the left = 1 and second thing is a right = 10 and last thing is a mid = 5
  
  
  so we will check the number 7 is more than the mid or less than the mid.
  
  
  if number 7 is more than mid the left will equal to mid + 1
  
  
  if number 7 less than mid the right will equal to mid - 1
  
  Code :
  
  const binarySearch = (sortedArr, value) => {
  
  let left = 0;
  
  let right = sortedArr.length - 1;
  
  
  while(left <= right) { const mid = Math.floor((left + right) / 2); const midVal = sortedArr[mid]; if(midVal === value) { return mid; } else if (midVal < value) { left = mid + 1;
  
  } else{
  
  right = mid - 1;
  
  }
  
  }
  
  return -1;
  
  };