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704 Binary Search

/**
 * 
 * Ashish Patel
 * e: ashishsushilPatel@gmail.com
 * w: https://ashish.me
 *
 */

/* 
 * Given a sorted (in ascending order) integer array nums of n elements and
 * a target value, write a function to search target in nums. If target
 * exists, then return its index, otherwise return -1.
 * 
 * 
 * Example 1:
 * 
 * Input: nums = [-1,0,3,5,9,12], target = 9
 * Output: 4
 * Explanation: 9 exists in nums and its index is 4
*/

function binarySearch(nums, target) {
  let start = 0
  let end = nums.length - 1
  let mid = 0
  while(start <= end){
    mid = parseInt((start + end)/2)
    if(nums[mid] === target){
      return mid
    }
    if(nums[mid] > target){
      end = mid - 1
    }
    if(nums[mid] < target){
      start = mid + 1
    }
  }
  return -1
}

test('binary Search', () => {
  expect(binarySearch([-1,0,3,5,9,12], 9)).toEqual(4)
});

Created 2020-04-10T21:10:16+00:00 · Edit