DAY7P1.md

Binary Search

---

• Question:

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1.

You must write an algorithm with O(log n) runtime complexity.

---

• Example:

Input: nums = [-1,0,3,5,9,12], target = 9

Output: 4

Explanation: 9 exists in nums and its index is 4

---

• Solution:

Code :

class Solution {
    public int search(int[] arr, int target) {
        int start=0;
        int end=arr.length-1;
        while(start<=end)
        {
            int mid=start+(end-start)/2;
            if(arr[mid]>target)
            {
                end=mid-1;
            }
            else if(arr[mid]<target)
            {
                start=mid+1;
            }
            else
                return mid;
                
        }
        return -1;
    }
}