Question

Given a sorted (in ascending order) integer array nums of n elements and a target value, write a method to perform a binary search for a target value in nums. If target exists, then return its index, otherwise return -1. Analyze the running time, T(n).

public int search(int[] nums, int target) {

// YOUR CODE GOES HERE

} // end search

Answer 1

public int search(int[] nums, int target) {
    int low = 0;
    int high = nums.length - 1;
    int mid;
    while (high >= low) {
        mid = (low + high) / 2;
        if (target == nums[mid])
            return mid;
        else if (target > nums[mid])
            low = mid + 1;
        else
            high = mid - 1;
    }
    return - 1;
}